Congress of the Association Internationale d' Experts Scientifiques du Tourisme Bulgary. (1979). Manpower in tourism: Proceedings of the 29th Congress of the Association Internationale d' Experts Scientifiques du Tourisme , Droujba pres de Varna (Bulgarie), 2-8 September 1979. AIEST.
Cita Chicago (17th ed.)Congress of the Association Internationale d' Experts Scientifiques du Tourisme Bulgary. Manpower in Tourism: Proceedings of the 29th Congress of the Association Internationale D' Experts Scientifiques Du Tourisme , Droujba Pres De Varna (Bulgarie), 2-8 September 1979. Berne, Switzerland: AIEST, 1979.
Cita MLA (9th ed.)Congress of the Association Internationale d' Experts Scientifiques du Tourisme Bulgary. Manpower in Tourism: Proceedings of the 29th Congress of the Association Internationale D' Experts Scientifiques Du Tourisme , Droujba Pres De Varna (Bulgarie), 2-8 September 1979. AIEST, 1979.