Elementary differential equations / by William Ted Martin and Eric Reissner. Martin, William Ted, 1911-2004. Reissner, Eric. Differential equations. QA372 .M38 1986 515.35 19 M383e Reprint. Originally published: 2nd ed. Reading, Mass. : Addison-Wesley Pub. Co., 1961. (Addison-Wesley series in mathematics) Includes index. New York : Dover Publications, 1986, c1961. 1986, c1961. 1986 Text xiii, 331 p. : eng