To cite this work in a bibliography:
Social Studies Fact Cards, "[title of card]," [url shown in the address box for that card] (accessed [date card was viewed by user])
Social Studies Fact Cards, "Mission Santa Cruz," http://online.toucanvalley.com/FactCards/mis/santacruz.html (accessed July 1, 2006).
Social Studies Fact Cards, "Mexico," http://online.toucanvalley.com/FactCards/cow/mexico.html (accessed September 18, 2006).
(source of citation format: The Chicago Manual of Style, 15th edition, University of Chicago Press, 2003).