APA (7th ed.) Citation

Kilpatrick, J. E., & Ford, D. I. (1969). Virial equation of state. American Journal of Physics, 37, 881.

Chicago Style (17th ed.) Citation

Kilpatrick, J. E., and D. I. Ford. "Virial Equation of State." American Journal of Physics 37 (1969): 881.

MLA (9th ed.) Citation

Kilpatrick, J. E., and D. I. Ford. "Virial Equation of State." American Journal of Physics, vol. 37, 1969, p. 881.