From the Country Studies web site:
For information about the title, editor, and date of information of a particular study, please refer to the first entry in the table of contents of the online study, which should be the name of the country. That information along with the Web site's URL can be included in your citation. The authors/editors of the various chapters of published Country Studies are listed in parentheses after the chapter titles in the Table of Contents of each online Country Study.
Example of APA citation:
Savada, A. M. (Ed.) (1994). Library of Congress country studies: Laos. Retrieved from http://memory.loc.gov/frd/cs/latoc.html