In this section: Personal communication: email message; letter; other (e.g. conversation) | Unpublished data | Figure, table or appendix in a journal article | Study listed in a trial register | Ongoing study (not listed in trial register) | Scientific or technical report | Supplementary materials | Epub ahead of print | Preprint

Personal communication: email message

Example: Smith A. Allocation concealment used in our trial [personal communication]. Email to: C Keystone 27 November 2009.

Personal communication: letter

Example: Smith A. (Vaccine Research Group, London, UK) [personal communication]. Letter to: C Keystone (Vaccine Review Study Team, London, UK) 27 November 2009.

Personal communication: other communication (e.g. conversation)

Example: Smith A. (Vaccine Research Group, London, UK). [personal communication]. Conversation with: C Keystone (Vaccine Review Study Team, London, UK) 27 November 2009.

Unpublished data

Example: UK/Asia trialists. Individual patient data (as supplied 1 April 1995). Data on file.

Figure, table or appendix in a journal article

Use this format when referencing a figure, table or appendix within a journal article, or when reproducing such material in a Cochrane Review.

Example: Osrin D, Vaidya A, Shrestha Y, Baniya RB, Manandhar DS, Adhikari RK, et al. Effects of antenatal multiple micronutrient supplementation on birthweight and gestational duration in Nepal: double-blind, randomised controlled trial. Lancet 2005;365(9463):955-62. Figure, Trial profile; p. 958.

Study listed in a trial register

Example: NCT00119132. Effectiveness of intermittent preventive treatment for malaria in children [Study of impact of intermittent preventive treatment in children with amodiaquine plus artesunate versus sulphadoxine-pyrimethamine on hemoglobin levels and malaria morbidity in Hohoe District of Ghana]. clinicaltrials.gov/show/NCT00119132 (first received 10 August 2005).

Ongoing study (not in trial register or journal)

Example: Der Hoeven EJRJ, Schonewille WJ, Vos JA. BASilar artery International Cooperation Study (BASICS) trial. www.basicstrial.com (accessed 1 June 2016).

Scientific or technical report

Example: Akutsu T. Total heart replacement device. Bethesda (MD): National Institutes of Health, National Heart and Lung Institute; 1974 April. Report No.: NIH NHLI 69 2185 4.

Supplementary materials

Supplementary materials could refer to data or other resources that are published as part of an article (so would have the same authors, date, and underlying source, but would be designated as supplementary material) or could refer to accompanying or linked materials (with different authors, title, date, etc). Therefore, when citing supplementary materials consider whether the materials are presented as part of the main article or as work that has been published independently from the main article.

For supplementary materials that are part of an article, cite the article as usual, but add the section name/number and title of the supplementary materials to the end of the reference. For further guidance and examples, refer to Citing Medicine: examples of citations to parts of journal articles.

For supplementary materials that are independent of the article, locate the primary source for the supplementary material and cite according to the reference type.

Electronic publication ahead of print

Example: Feldman RD, Zou GY, Vandervoort MK, Wong CJ, Nelson SA, Feagan BG. A simplified approach to the treatment of uncomplicated hypertension. A cluster randomized, controlled trial. Hypertension 2009 Feb 23 [Epub ahead of print]. [DOI: https://doi.org/10.1161/HYPERTENSIONAHA.108.123455]

Preprint

Example: Blanchard AC, Desforges M, Labbé AC, Nguyen CT, Petit Y, Besner D, et al. Evaluation of real-life use of Point-of-Care Rapid Antigen TEsting for SARS-CoV-2 in schools (EPOCRATES). MedRxiv 2022 [Preprint]. [DOI:  https://doi.org/10.1101/2021/10.13.21264960]