When doing research, you are often building on the work of others and will sometimes take an idea, fact or quotation from someone else's work such as a book or article. If you are including such ideas/facts/quotations on your poster, you must cite your sources to give credit to other researchers and writers and so others can trace your research or retrieve the source material. The same is true for other kinds of sources such as pictures or other graphics that may be incorporated into the design of your poster.
If you have a handout to accompany your poster, you may list your references on that. If not, you should list them in small type at the bottom of the poster.
Different meeting sponsors/organizations may have differing styles for formatting citations. Use the style required in the abstract/poster guidelines or your research advisor
Posters presented at meetings include both items that were only presented in this way or those which were followed by a publication. If you do follow a poster with a publication, cite that subsequent work on your CV rather than the meeting poster.
Regardless of the style you follow, elements for the citation will be the same: Author name(s), title of the poster, title of the conference/meeting, date, location. The conference may also have a descriptive "name" as well as a title.
Contributor, A. A., Contributor, B. B., Contributor, C. C., & Contributor, D. D. (Year, Month Day). Title of contribution [Description of contribution]. Title of Symposium/Conference, Location. URL (optional)
Matson, E. (2018, November 5). Drones and autonomous vehicles: The latest new technology to come with potential threat [Poster presentation]. Dawn or Doom 2018 Conference, Purdue University, West Lafayette, IN, United States.
Pearson, J. (2018, September 27-30). Fat talk and its effects on state-based body image in women [Poster presentation]. Australian Psychological Society Congress, Sydney, NSW, Australia. http://bit.ly/2XGSThP
Author AA, Author BB, Author CC. Title of poster. Poster presented at: Name of conference; Month, Day Year; City, State abbreviation.
Smyth ME, Caurdy-Bess L. Legal aid for children: a medical-legal partnership supported by CATCH funding. Poster presented at: 2010 Medical-Legal Partnership Summit; March, 2010; Arlington, VA.
Pasternak B. Carvedilol vs metoprolol succinate and risk of mortality in patients with heart failure: national cohort study. Paper presented at: European Society of Cardiology Congress; August 31, 2014; Barcelona, Spain.