ICPSR studies can be cited by clicking the Cite This Study link in an item record, and either copying/pasting the citation or exporting it to a citation manager.
Whatever citation style is used, the essential elements of a data citation are:
Some examples:
ABC News, and The Washington Post. ABC News/Washington Post Poll, May 2007 [Computer file]. ICPSR24588-v1. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2009-04-17. doi:10.3886/ICPSR24588
United States Department of Commerce. Bureau of the Census, and United States Department of Labor. Bureau of Labor Statistics. Current Population Survey: Annual Demographic File, 1987 [Computer file]. ICPSR08863-v2. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2009-02-03. doi:10.3886/ICPSR08863
See ICPSR's guide to proper research data citation for more resources on this topic.