APA
Hopf L., . (1948). Introduction to the differential equations of physics. [s.l.]: [s.n.].
Chicago
Hopf Ludwig, . 1948. Introduction to the differential equations of physics. [s.l.]: [s.n.].
Harvard
Hopf L., . (1948). Introduction to the differential equations of physics. [s.l.]: [s.n.].
MLA
Hopf Ludwig, . Introduction to the differential equations of physics. [s.l.]: [s.n.]. 1948.