SIMPSON, O. (2003). Student retention in online, open and distance learning. Kogan page.
Chicago-čujuhus (17. p.)SIMPSON, Ormond. Student Retention in Online, Open and Distance Learning. Kogan page, 2003.
MLA-čujuhus (9. p.)SIMPSON, Ormond. Student Retention in Online, Open and Distance Learning. Kogan page, 2003.
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