Petrovsky, I. G. Ordinary differential equations/ [by] I.G. Petrovski. - Rev. English ed., translated and edited by Richard A. Silverman. - Englewood Cliffs, N.J.: Prentice-Hall, [1966]. - x, 232 p.: illus., 24 cm. Bibliography: p. 227. LCCN: 66018161 Nat. Bib. No.: GB67-1933 Subjects--Topical Terms: Differential equations. Dewey Class. No.: 515.35 / P497o