Vintage 1935 Elementary Differential Equations by Lyman Kells (USNA) HC 2nd Ed

Elementary Partial Differential Equations by Berg & McGregor (1966 VTG HC)

The Theory of Ordinary Differential Equations University Mathematical Texts HC

Differential Equations for Engineers by Philip Franklin 1960 Mathematics MIT

Elementary Differential Equations By Lyman M. Kells Vintage 1947 HC Illus. Math

An Elementary Treatise on Differential Equations H.T.H. Piaggio 1965 reprint.