Bogoliubov, N. N., & Mitropolskii, I. A. (1961). Asymptotic methods in the theory of non-linear oscillations ([2nd ed.].). Hindustan Pub. Corp. : Gordon and Breach Science Publishers.

Bogoliubov, N. N., and IU. A. Mitropolskii. Asymptotic Methods in the Theory of Non-linear Oscillations. [2nd ed.]. Delhi : New York: Hindustan Pub. Corp. : Gordon and Breach Science Publishers, 1961.

Bogoliubov, N. N., and IU. A. Mitropolskii. Asymptotic Methods in the Theory of Non-linear Oscillations. [2nd ed.]. Hindustan Pub. Corp. : Gordon and Breach Science Publishers, 1961.