APA (7th ed.) Zitazioa
Schuller, R. H. (1983). Tough times never last, but tough people do. Thomas Nelson.
Chicago Style (17th ed.) Zitazioa
Schuller, Robert H. Tough Times Never Last, but Tough People Do. New York: Thomas Nelson, 1983.
MLA (9th ed.) Zitazioa
Schuller, Robert H. Tough Times Never Last, but Tough People Do. Thomas Nelson, 1983.
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