Gaya APA

Gilbeart, H, C. (1955). Commercial Ferilizers Their Sources and Use (5th). United State of America: McGraw-Hill Book Company, Inc.

Gaya MLA

Gilbeart, H., Collings,. "Commercial Ferilizers Their Sources and Use". 5th United State of America: McGraw-Hill Book Company, Inc, 1955. Text.