APA (7th ed.) Citation

Helms, L. L. (1969). Introduction to potential theory. Wiley Interscience.

Chicago Style (17th ed.) Citation

Helms, L. L. Introduction to Potential Theory. New York: Wiley Interscience, 1969.

MLA (8th ed.) Citation

Helms, L. L. Introduction to Potential Theory. Wiley Interscience, 1969.

Warning: These citations may not always be 100% accurate.