Postgate, Richmond Seymour Postgate, Richmond Seymour Open learning: system and problems in post-secondary education Open learning: system and problems in post-secondary education - Paris Paris UNESCO Press UNESCO Press 1975 1975 - 498p. 498p. 24cm. 24cm. Subjects--Topical Terms: University extensionUniversity extension LC Class. No.: C6223.M32 C6223.M32