Note that PMIDs and PMCIDs are not the same. You can find PMCIDs in both PubMed and PubMed Central.
NIH requires investigators to include the PubMed Central reference number (PMCID) in all subsequent NIH grant applications, proposals, and progress reports as evidence of compliance. Include the PMCID at the end of citations.
For papers published more than 3 months before an application, proposal or report is submitted:
List the PubMed Central reference number (PMCID) at the end of the full journal citation for the paper in NIH applications, proposals and reports. A PMCID is the only way to demonstrate compliance for these papers.
For papers in press, or published within 3 months of when an application, proposal or report is submitted:
Effective August 21, 2009, an NIHMSID may be used to indicate compliance with the Public Access Policy for up to three months after a paper is published. After that period, a PMCID must be provided in order to indicate compliance.
Examples (PMCID available):
Sala-Torra O, Gundacker HM, Stirewalt DL, Ladne PA, Pogosova-Agadjanyan EL, Slovak ML, Willman CL, Heimfeld S, Boldt DH, Radich JP. Connective tissue growth factor (CTGF) expression and outcome in adult patients with acute lymphoblastic leukemia. Blood. 2007 April 1; 109(7): 3080–3083. PMCID: PMC1852221
Cerrato A, Parisi M, Santa Anna S, Missirlis F, Guru S, Agarwal S, Sturgill D, Talbot T, Spiegel A, Collins F, Chandrasekharappa S, Marx S, Oliver B. Genetic interactions between Drosophila melanogaster menin and Jun/Fos. Dev Biol. 2006 Oct 1; 298(1): 59-70. PMCID: PMC2291284
Examples (PMCID not yet available: 3-month limit):
Journal Method A or B, use "PMC Journal - In Process": Sala-Torra O, Gundacker HM, Stirewalt DL, Ladne PA, Pogosova-Agadjanyan EL, Slovak ML, Willman CL, Heimfeld S, Boldt DH, Radich JP. Connective tissue growth factor (CTGF) expression and outcome in adult patients with acute lymphoblastic leukemia. Blood. [a publication date within 3 months of when the application, proposal or report was submitted to NIH]. PMCID: PMC Journal - In Process
Journal Method C or D, use the NIHMSID: Cerrato A, Parisi M, Santa Anna S, Missirlis F, Guru S, Agarwal S, Sturgill D, Talbot T, Spiegel A, Collins F, Chandrasekharappa S, Marx S, Oliver B. Genetic interactions between Drosophila melanogaster menin and Jun/Fos. Dev Biol. In press. NIHMSID: NIHMS44135
Use the NIH style to automatically have EndNote include the PMCID at the end of your citation.
EndNote X3 and later come with updated files that import the PMC number to the PMC field automatically.