APA

United States, . (1991). Commercial library publications list, 1991-1992. Washington: Dept. of State Library.

Chicago

United States, . 1991. Commercial library publications list, 1991-1992. Washington: Dept. of State Library.

Harvard

United States, . (1991). Commercial library publications list, 1991-1992. Washington: Dept. of State Library.

MLA

United States, . Commercial library publications list, 1991-1992. Washington: Dept. of State Library. 1991.