Cita APA (7th ed.)
Purcell, E. J., & Varberg, D. E. (1987). Calculus with analytic geometry (5th ed.). Prentice-Hall.
Cita Chicago (17th ed.)
Purcell, Edwin J., i Dale E. Varberg. Calculus with Analytic Geometry. 5th ed. Englewood Cliffs, N.J.: Prentice-Hall, 1987.
Cita MLA (9th ed.)
Purcell, Edwin J., i Dale E. Varberg. Calculus with Analytic Geometry. 5th ed. Prentice-Hall, 1987.
Atenció: Aquestes cites poden no estar 100% correctes.