Smith, G. M., Gilbert, E. M., Evans, R. I., Duggar, B. M., Bryan, G. S., & Allen, C. E. (1945). A textbook of general botany (4th.). New York: The Macmillan Company.

Smith, Gilbert Morgan,, Edward Martinius Gilbert, Richard Irving Evans, Benjamin Minge Duggar, George S. Bryan, and Charles Elmer Allen. A Textbook of General Botany. 4th. New York: The Macmillan Company, 1945.

Smith, Gilbert Morgan,, et al. A Textbook of General Botany. 4th. New York: The Macmillan Company, 1945.