The sheep and lamb situation ... :
SLS 1-30. Jan. 1937-June 1939.

APA Citation

United States. Bureau of Agricultural Economics. (19371939). The sheep and lamb situation ...: SLS 1-30. Jan. 1937-June 1939. Washington: U.S. Dept. of agriculture, Bureau of agricultural economics.

MLA Citation

United States. Bureau of Agricultural Economics. The Sheep And Lamb Situation ...: SLS 1-30. Jan. 1937-June 1939. Washington: U.S. Dept. of agriculture, Bureau of agricultural economics, 19371939.

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