Não informado. Educators guide to free filmstrips. Educators Progress Service.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Educators Guide to Free Filmstrips. Randolph, Wis: Educators Progress Service.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Educators Guide to Free Filmstrips. Educators Progress Service.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.