(Q37251721)

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

title

Principles of long-term dynamics of dendritic spines (English)

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

1 reference

2

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

Haruo Kasai

series ordinal

5

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

4

Jun Noguchi

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

author name string

Nobuaki Yasumatsu

series ordinal

1

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

Takashi Miyazaki

series ordinal

3

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

language of work or name

English

0 references

publication date

1 December 2008

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

published in

Journal of Neuroscience

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

volume

28

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

issue

50

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

page(s)

13592-13608

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

Spine expansion and stabilization associated with long-term potentiation

18 January 2020

cites work

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

The subspine organization of actin fibers regulates the structure and plasticity of dendritic spines

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Protein synthesis and neurotrophin-dependent structural plasticity of single dendritic spines.

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Smaller dendritic spines, weaker synaptic transmission, but enhanced spatial learning in mice lacking Shank1.

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Regulation of spine morphology and spine density by NMDA receptor signaling in vivo

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Adhesion molecules in the nervous system: structural insights into function and diversity

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Natural oligomers of the Alzheimer amyloid-beta protein induce reversible synapse loss by modulating an NMDA-type glutamate receptor-dependent signaling pathway

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Neurexin-neuroligin signaling in synapse development

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Synapse-specific regulation of AMPA receptor function by PSD-95.

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Rapid redistribution of synaptic PSD-95 in the neocortex in vivo

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Experience-dependent and cell-type-specific spine growth in the neocortex.

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Long-term sensory deprivation prevents dendritic spine loss in primary somatosensory cortex

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Spine-neck geometry determines NMDA receptor-dependent Ca2+ signaling in dendrites.

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Development of long-term dendritic spine stability in diverse regions of cerebral cortex

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Cascade models of synaptically stored memories

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Memory retention--the synaptic stability versus plasticity dilemma

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Transient and persistent dendritic spines in the neocortex in vivo

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Shrinkage of dendritic spines associated with long-term depression of hippocampal synapses

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

New circuits for old memories: the role of the neocortex in consolidation

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Structural basis of long-term potentiation in single dendritic spines

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Structure-stability-function relationships of dendritic spines

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Structural changes at dendritic spine synapses during long-term potentiation

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

How long will long-term potentiation last?

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Long-term in vivo imaging of experience-dependent synaptic plasticity in adult cortex

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Interactions among toxins that inhibit N-type and P-type calcium channels

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Dendritic spine geometry is critical for AMPA receptor expression in hippocampal CA1 pyramidal neurons

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Hebb and homeostasis in neuronal plasticity

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

NMDA spikes in basal dendrites of cortical pyramidal neurons

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Synapse elimination and indelible memory

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Dendritic spine changes associated with hippocampal long-term synaptic plasticity

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Rapid Dendritic Morphogenesis in CA1 Hippocampal Dendrites Induced by Synaptic Activity

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Synaptogenesis via dendritic filopodia in developing hippocampal area CA1.

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Activity-dependent scaling of quantal amplitude in neocortical neurons

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

A mechanism for the Hebb and the anti-Hebb processes underlying learning and memory

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

A stochastic method to predict the consequence of arbitrary forms of spike-timing-dependent plasticity.

6 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Selective peptide antagonist of the class E calcium channel from the venom of the tarantula Hysterocrates gigas

14 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Rapid actin-based plasticity in dendritic spines

28 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Surface mobility of postsynaptic AMPARs tunes synaptic transmission

28 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Synaptic metaplasticity through NMDA receptor lateral diffusion.

26 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Synaptic strength of individual spines correlates with bound Ca2+-calmodulin-dependent kinase II.

26 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Density and morphology of dendritic spines in mouse neocortex.

26 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Cortical area and species differences in dendritic spine morphology

26 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Selective induction of LTP and LTD by postsynaptic [Ca2+]i elevation

26 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Activity regulates the synaptic localization of the NMDA receptor in hippocampal neurons.

26 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Contrasting biophysical and pharmacological properties of T-type and R-type calcium channels.

26 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Activity-dependent regulation of dendritic spine density on cortical pyramidal neurons in organotypic slice cultures

26 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Dihydropyridine-sensitive and omega-conotoxin-sensitive calcium channels in a mammalian neuroblastoma-glioma cell line

26 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Independent expression of synaptic and morphological plasticity associated with long-term depression

26 June 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Protracted synaptogenesis after activity-dependent spinogenesis in hippocampal neurons.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Distinct structural and ionotropic roles of NMDA receptors in controlling spine and synapse stability.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Nonlinear regulation of unitary synaptic signals by CaV(2.3) voltage-sensitive calcium channels located in dendritic spines

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Spine growth precedes synapse formation in the adult neocortex in vivo.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Miniature synaptic currents become neurotoxic to chronically silenced neurons.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Miniature neurotransmission stabilizes synaptic function via tonic suppression of local dendritic protein synthesis.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Relation between single neuron and population spiking statistics and effects on network activity.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Glutamate receptor exocytosis and spine enlargement during chemically induced long-term potentiation.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Activity-dependent dendritic spine structural plasticity is regulated by small GTPase Rap1 and its target AF-6.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Bidirectional activity-dependent morphological plasticity in hippocampal neurons

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Imaging the motility of dendritic protrusions and axon terminals: roles in axon sampling and synaptic competition

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Quaternary structure, protein dynamics, and synaptic function of SAP97 controlled by L27 domain interactions

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Persistent accumulation of calcium/calmodulin-dependent protein kinase II in dendritic spines after induction of NMDA receptor-dependent chemical long-term potentiation.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Rapid and persistent modulation of actin dynamics regulates postsynaptic reorganization underlying bidirectional plasticity.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Development of rat CA1 neurones in acute versus organotypic slices: role of experience in synaptic morphology and activity.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Mechanism of the distance-dependent scaling of Schaffer collateral synapses in rat CA1 pyramidal neurons.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Activity blockade increases the number of functional synapses in the hippocampus of newborn rats

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Long-term dendritic spine stability in the adult cortex

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Dendritic spikes as a mechanism for cooperative long-term potentiation.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

NMDA receptor activation limits the number of synaptic connections during hippocampal development.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Fokker-Planck approach to the pulse packet propagation in synfire chain

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Continual remodeling of postsynaptic density and its regulation by synaptic activity

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Different modes of expression of AMPA and NMDA receptors in hippocampal synapses

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Miniature synaptic events maintain dendritic spines via AMPA receptor activation

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Cell type and pathway dependence of synaptic AMPA receptor number and variability in the hippocampus.

3 September 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2706274

Dendritic spines of CA 1 pyramidal cells in the rat hippocampus: serial electron microscopy with reference to their biophysical characteristics

3 September 2018

1 reference

PubMed

https://pubmed.ncbi.nlm.nih.gov/19074033

inferred from PubMed ID database lookup

12 December 2020

based on heuristic

Dendritic Spine Pathology: Cause or Consequence of Neurological Disorders?

1 reference

PubMed

https://pubmed.ncbi.nlm.nih.gov/19074033

inferred from PubMed ID database lookup

12 December 2020

based on heuristic

Identifiers

DOI

10.1523/JNEUROSCI.0603-08.2008

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

1 reference

https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=EXT_ID:19074033%20AND%20SRC:MED&resulttype=core&format=json

18 January 2020

PubMed publication ID

19074033

1 reference