SIMPSON, O. (2003). Student retention in online, open and distance learning. Kogan page.
Čikaški stil citiranja (17. izdanje)SIMPSON, Ormond. Student Retention in Online, Open and Distance Learning. Kogan page, 2003.
MLA način citiranja (9. izdanje)SIMPSON, Ormond. Student Retention in Online, Open and Distance Learning. Kogan page, 2003.
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