Keng Hua Loo Second-order systems of partial differential equations of the plane Keng Hua Loo; Wei Lin; Ci-Quian Wu - Boston Pitman 1985 - p. cm. - Research notes in mathematics; 128 . Includes bibliography Standard No.: 22719 Source: Textual Subjects--Topical Terms: Differential equations Dewey Class. No.: B334, M5