A supplement to Regional or district libraries :
regional and contract library laws passed, 1939-40.

APA Citation

American Library Association. (1940). A supplement to Regional or district libraries: regional and contract library laws passed, 1939-40. Chicago: American Library Association.

MLA Citation

American Library Association. A Supplement to Regional Or District Libraries: Regional And Contract Library Laws Passed, 1939-40. Chicago: American Library Association, 1940.

Warning: These citations may not always be complete (especially for serials).