Gas, air and spring guns of the world.

MLA

Smithn, W. H. B. Gas, Air and Spring Guns of the World. Harrisburg, 1957.

APA

Smithn, W. H. B. (1957). Gas, air and spring guns of the world. Harrisburg.

Chicago

Smithn, W. H. B. Gas, Air and Spring Guns of the World. Harrisburg, 1957.