APA

Funk W. L. N., . (1942). 30 days to a more powerful vocabulary. : Pocket Books, New York.

Chicago

Funk Wilfred Lewis Norman, . 1942. 30 days to a more powerful vocabulary. : Pocket Books, New York.

Harvard

Funk W. L. N., . (1942). 30 days to a more powerful vocabulary. : Pocket Books, New York.

MLA

Funk Wilfred Lewis Norman, . 30 days to a more powerful vocabulary. : Pocket Books, New York. 1942.