Cita APA (7th ed.)
Hetao Liu, J. A First Course in the Qualitative Theory of Differential Equations. Prentice-Hall.
Cita Chicago (17th ed.)
Hetao Liu, James. A First Course in the Qualitative Theory of Differential Equations. Upper Saddle River, EUA: Prentice-Hall.
Cita MLA (9th ed.)
Hetao Liu, James. A First Course in the Qualitative Theory of Differential Equations. Prentice-Hall.
Atenció: Aquestes cites poden no estar 100% correctes.