Polit, D. F. (1991). Nursing research: Principles and methods (4th ed.). Lippincott.
Chicago-viite (17. p.)Polit, Denise F. Nursing Research: Principles and Methods. 4th ed. Philadelphia: Lippincott, 1991.
MLA-viite (8. p.)Polit, Denise F. Nursing Research: Principles and Methods. 4th ed. Lippincott, 1991.
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