Montana :
a State guide book /
compiled and written by the Federal Writers' Project of the Work Projects Administration for the State of Montana. New York, Viking Press, 1939.

APA Citation

Federal Writers' Project. Montana. (1973). Montana: a State guide book. St. Clair Shores, Mich.: Somerset Publishers.

MLA Citation

Federal Writers' Project. Montana. Montana: a State Guide Book. St. Clair Shores, Mich.: Somerset Publishers, 1973.

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