Cita APA (7th ed.)
Schuller, R. H. (1983). Tough times never last, but tough people do. Thomas Nelson.
Cita Chicago (17th ed.)
Schuller, Robert H. Tough Times Never Last, but Tough People Do. New York: Thomas Nelson, 1983.
Cita MLA (9th ed.)
Schuller, Robert H. Tough Times Never Last, but Tough People Do. Thomas Nelson, 1983.
Atenció: Aquestes cites poden no estar 100% correctes.