Παραπομπή APA

Petrovsky, I. G. (1964). Lectures on partial differential equations.

Παραπομπή Chicago Style

Petrovsky, I G. Lectures on Partial Differential Equations. Dover Publication, New York, 1964.

Παραπομπή MLA

Petrovsky, I G. Lectures on Partial Differential Equations. 1964.