Waltin, W. R. (1921). The green-bug or spring grain-aphis: How to prevent its periodical outbreaks. U.S. Dept. of Agriculture.
Chicago-Zitierstil (17. Ausg.)Waltin, William Randolph. The Green-bug or Spring Grain-aphis: How to Prevent Its Periodical Outbreaks. Washington, D.C: U.S. Dept. of Agriculture, 1921.
MLA-Zitierstil (9. Ausg.)Waltin, William Randolph. The Green-bug or Spring Grain-aphis: How to Prevent Its Periodical Outbreaks. U.S. Dept. of Agriculture, 1921.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.