APA-čujuhus (7. p.)
Friend, D. V. (1987). Quantitative methods. Longman.
Chicago-čujuhus (17. p.)
Friend, D. V. Quantitative Methods. London ; New York: Longman, 1987.
MLA-čujuhus (9. p.)
Friend, D. V. Quantitative Methods. Longman, 1987.
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