APA (7th ed.) Citation

Skilling, W. T. (1920). Nature-study agriculture: A textbook for beginners. World book company.

Chicago Style (17th ed.) Citation

Skilling, William Thompson. Nature-study Agriculture: A Textbook for Beginners. Yonkers-on-Hudson, N. Y.: World book company, 1920.

MLA (9th ed.) Citation

Skilling, William Thompson. Nature-study Agriculture: A Textbook for Beginners. World book company, 1920.