Betz, H., Burcham, P. B., & Ewing, G. M. [ca. 1964]. Differential equations with applications. In Harperś mathematics series (2. ed.) [Book]. New York: Harper & Row.

BETZ, Herman, BURCHAM, Paul B. und EWING, George M., 1964. Differential equations with applications. 2. ed. New York: Harper & Row.

Betz, H., P. B. Burcham, und G. M. Ewing. „Differential equations with applications“. Harperś mathematics series, 2. ed., book, Harper & Row, 1964.

Betz, Herman/Burcham, Paul B./Ewing, George M.: Differential equations with applications, 2. ed. Aufl. New York 1964.

Betz, H., Burcham, P.B. und Ewing, G.M. (1964), Differential equations with applications, Harperś mathematics series, 2. ed., Bd. , Harper & Row, New York.