Suediniavaneto na obuchenieto s proizvoditelniia trud kato pedagogicheski printsip
Publisher: Izd. na Bulg. akad. na naukite
Published: 1961
Place of publication: Sofiia
Language: bul
Number of pages: 146
Notes: At head of title: Bulgarska akademiia na naukite. Pedagogicheski institut.

Russian and French summaries.