APA (7th ed.) Citation

Richards, W. (1994). Energy levels in atoms and molecules. Oxford Univ. Pr..

Chicago Style (17th ed.) Citation

Richards, W.G. Energy Levels in Atoms and Molecules. Oxford: Oxford Univ. Pr., 1994.

MLA (9th ed.) Citation

Richards, W.G. Energy Levels in Atoms and Molecules. Oxford Univ. Pr., 1994.