In 1987, the National Commission on Libraries and Information Science, the American Library Association, and libraries across the U.S. began the campaign to put a library card in the hands of every school child in America. In 1988, the campaign moved to September, where it remains.
"National library card campaign kicked off on D.C. Mall." School Library Journal 34, (December 1987): 13.
"September to be national library card sign-up time." American Libraries 19, no. 6 (June 1988): 524.
Wallace, Linda. "Library Card Campaign Launched In Year Of The Reader." ALA Yearbook Of Library & Information Services, v13, 1988 (1988): 106-7.