(Q36381705)

13 August 2017

Hip ontogenesis: how evolution, genes, and load history shape hip morphotype and cartilotype (English)

1 reference

13 August 2017

1 reference

Tom Hogervorst

1

1 reference

13 August 2017

Wouter Eilander

series ordinal

2

1 reference

13 August 2017

Joost T Fikkers

series ordinal

3

1 reference

13 August 2017

Ingrid Meulenbelt

series ordinal

4

1 reference

13 August 2017

language of work or name

English

0 references

publication date

1 December 2012

1 reference

Clinical Orthopaedics and Related Research

13 August 2017

1 reference

13 August 2017

470

1 reference

13 August 2017

12

1 reference

13 August 2017

3284-3296

1 reference

Variant alleles of the Wnt antagonist FRZB are determinants of hip shape and modify the relationship between hip shape and osteoarthritis

13 August 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Screening for developmental dysplasia of the hip in Hong Kong

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

The cam-type deformity of the proximal femur arises in childhood in response to vigorous sporting activity

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

The association between hip morphology parameters and nineteen-year risk of end-stage osteoarthritis of the hip: a nested case-control study

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Advances in magnetic resonance imaging of articular cartilage.

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Morphologic differences between the hips of Chinese women and white women: could they account for the ethnic difference in the prevalence of hip osteoarthritis?

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Expression of the osteoarthritis-associated gene GDF5 is modulated epigenetically by DNA methylation.

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Prevalence of radiographic findings thought to be associated with femoroacetabular impingement in a population-based cohort of 2081 healthy young adults

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Study of femoral torsion during prenatal growth: interpretations associated with the effects of intrauterine pressure

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Mechanical influences on morphogenesis of the knee joint revealed through morphological, molecular and computational analysis of immobilised embryos

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Association of the D repeat polymorphism in the ASPN gene with developmental dysplasia of the hip: a case-control study in Han Chinese

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Hundreds of variants clustered in genomic loci and biological pathways affect human height

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

The GDF5 rs143383 polymorphism is associated with osteoarthritis of the knee with genome-wide statistical significance

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Mechanobiology of embryonic skeletal development: Insights from animal models

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Exome sequencing: the sweet spot before whole genomes

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Validation of statistical shape model based reconstruction of the proximal femur--A morphology study

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Femoroacetabular impingement and classification of the cam deformity: the reference interval in normal hips

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

The genetic epidemiology of osteoarthritis

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Congenital Deformities of Mechanical Origin: (Section for the Study of Disease in Children).

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Familial predisposition to developmental dysplasia of the hip.

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

The association of proximal femoral shape and incident radiographic hip OA in elderly women

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Prevalence of femoroacetabular impingement in Asian patients with osteoarthritis of the hip.

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Identification of mechanosensitive genes during embryonic bone formation

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Proximal femoral anatomy in the normal human population

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

New insights into osteoarthritis: early developmental features of an ageing-related disease.

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Hip damage occurs at the zone of femoroacetabular impingement.

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

The etiology of osteoarthritis of the hip: an integrated mechanical concept

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Femoral anteversion: a necessary angle or an evolutionary vestige?

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

The control of chondrogenesis

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Idiopathic slipped capital femoral epiphysis in Amish children

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Multiple congenital dislocations associated with characteristic facial abnormality

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

The contour of the femoral head-neck junction as a predictor for the risk of anterior impingement

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Effects of biomechanical stress on bones in animals

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Subclinical slipped capital femoral epiphysis. Relationship to osteoarthrosis of the hip.

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Ontogeny of locomotion in mountain gorillas and chimpanzees

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Hip joint loading during walking and running, measured in two patients.

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Morphometric study of the fetal development of the human hip joint: significance for congenital hip disease.

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Histological study of the fetal development of the human acetabulum and labrum: significance in congenital hip disease

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Pierre Le Damany on congenital dysplasia of the hip.

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Natural history of congenital hip dislocation (CDH) and hip dysplasia

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

The effects of contact pressure elevations and aseptic necrosis on the long-term outcome of congenital hip dislocation.

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

The VCL hypothesis revisited: patterns of femoral morphology among quadrupedal and saltatorial prosimian primates

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Hip anatomy and ontogeny of lower limb musculature in three species of nonhuman primates

30 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Genetic influences in the aetiology of femoroacetabular impingement: a sibling study.

28 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Do normal radiographs exclude asphericity of the femoral head-neck junction?

28 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Mechanically modulated cartilage growth may regulate joint surface morphogenesis

28 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Developmental dysplasia of the hip in South Australia in 1991: prevalence and risk factors.

28 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Allometry and heterochrony in the African apes

28 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Diseases of the hip. A comparative study of Japanese Oriental and American white patients

28 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Etiology of osteoarthritis of the hip.

28 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Relationship between the sphericity of femoral head-acetabulum and the low incidence of primary osteoarthritis of the hip joint in Koreans

28 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Normal hip and knee active range of motion: the relationship to age.

28 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

The development of Cam-type deformity in adolescent and young male soccer players.

28 June 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Predictors of progression of osteoarthritis in femoroacetabular impingement: a radiological study with a minimum of ten years follow-up.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Selective activation of the MEK-ERK pathway is regulated by mechanical stimuli in forming joints and promotes pericellular matrix formation

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Hip joint forces in sheep.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Developmental dysplasia of the hip in twins: the importance of mechanical factors in the etiology of DDH.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Prevalence of malformations of the hip joint and their relationship to sex, groin pain, and risk of osteoarthritis: a population-based survey.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Occlusal asymmetries in children with congenital hip dislocation.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Total hip arthroplasty in patients with high dislocation: a concise follow-up, at a minimum of fifteen years, of previous reports.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Prevalence of hip osteoarthritis and acetabular dysplasia in french and japanese adults.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Anatomical study of the proximal femur in the fetus

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Muscle contraction is necessary to maintain joint progenitor cell fate

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Differential regulation of GDF-5 and FGF-2/4 by immobilisation in ovo exposes distinct roles in joint formation

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Association of mild acetabular dysplasia with an increased risk of incident hip osteoarthritis in elderly white women: the study of osteoporotic fractures

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Genetics of osteoarthritis.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Identification of DIO2 as a new susceptibility locus for symptomatic osteoarthritis

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

A functional polymorphism in the 5' UTR of GDF5 is associated with susceptibility to osteoarthritis

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Gender differences in 3D morphology and bony impingement of human hips

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Slipped capital femoral epiphysis: rising rates with obesity and aboriginality in South Australia

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Mechanobiological predictions of growth front morphology in developmental hip dysplasia.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Epidemiology and demographics of slipped capital femoral epiphysis in Korea: a multicenter study by the Korean Pediatric Orthopedic Society.

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Genetic variation in the SMAD3 gene is associated with hip and knee osteoarthritis

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

An examination of the association between different morphotypes of femoroacetabular impingement in asymptomatic subjects and the development of osteoarthritis of the hip.

21 January 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Asporin and transforming growth factor-beta gene expression in osteoblasts from subchondral bone and osteophytes in osteoarthritis

21 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Acetabular dysplasia and hip osteoarthritis in Britain and Japan.

21 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Short adolescence in early hominids: infantile and adolescent growth of the human femur

21 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

The demographics of slipped capital femoral epiphysis. An international multicenter study.

21 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Walking, running, and sprinting: a three-dimensional analysis of kinematics and kinetics

21 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Prevalence of cam-type deformity on hip magnetic resonance imaging in young males: A cross-sectional study

21 September 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Early identification of radiographic osteoarthritis of the hip using an active shape model to quantify changes in bone morphometric features: Can hip shape tell us anything about the progression of osteoarthritis?

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

Normal Range of Motion of the Hip, Knee and Ankle Joints in Male Subjects, 30–40 Years of Age

21 January 2018

1 reference

https://api.crossref.org/works/10.1007%2FS11999-012-2511-4

How the horse moves: 2. Significance of graphical representations of equine hind limb kinematics

21 January 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=3492609

Osteoarthritis of the hip in a gorilla; report of a third case

21 October 2018

1 reference

12 December 2020

Osteoarthritis susceptibility genes influence the association between hip morphology and osteoarthritis

1 reference

12 December 2020

Slipped capital femoral epiphysis: early mechanical damage to the acetabular cartilage by a prominent femoral metaphysis

1 reference

12 December 2020

Positive effects of moderate exercise on glycosaminoglycan content in knee cartilage: a four-month, randomized, controlled trial in patients at risk of osteoarthritis

1 reference

12 December 2020

The effectiveness of a programme for neonatal hip screening over a period of 40 years: a follow-up of the New Plymouth experience

1 reference

12 December 2020

Athletic activity in adolescence as an etiological factor in degenerative hip disease

1 reference

12 December 2020

Prevalence of cam-type femoroacetabular impingement morphology in asymptomatic volunteers

1 reference

12 December 2020

The aetiology of primary osteoarthritis of the hip

1 reference

12 December 2020

A new radiological index for assessing asphericity of the femoral head in cam impingement

1 reference

12 December 2020

Three-dimensional computed tomography of the hip in the assessment of femoroacetabular impingement

1 reference

12 December 2020

Femoroacetabular impingement and the cam-effect. A MRI-based quantitative anatomical study of the femoral head-neck offset

1 reference

12 December 2020

An examination chair to measure internal rotation of the hip in routine settings: a validation study

1 reference

12 December 2020

Changes in shape of the human hip joint during its development and their relation to its stability

1 reference

12 December 2020

Influences of mechanical stress on prenatal and postnatal skeletal development

1 reference

12 December 2020

Femoral anteversion in the rabbit

1 reference

12 December 2020

Diagnostic procedures and surgical treatment of craniodorsal coxofemoral luxation in calves

1 reference

12 December 2020

Changing incidence of slipped capital femoral epiphysis: a relationship with obesity?

1 reference

12 December 2020

GDF5 deficiency in mice is associated with instability-driven joint damage, gait and subchondral bone changes

1 reference

12 December 2020

Nonspherical femoral head shape (pistol grip deformity), neck shaft angle, and risk of hip osteoarthritis: A case-control study

1 reference

12 December 2020

Articular cartilage and biomechanical properties of the long bones in Frzb-knockout mice

1 reference

12 December 2020

Long bone development in extrinsic fetal akinesia: an experimental study in rat fetuses subjected to oligohydramnios

1 reference

12 December 2020

Vertebral shape: automatic measurement with active shape models

1 reference

12 December 2020

10.1007/S11999-012-2511-4

Identifiers

DOI

1 reference

13 August 2017

1 reference

13 August 2017

PubMed publication ID

22926490

1 reference