Dyulgerov N. (1989). Nature protection is a social necessity: Chairman of the Commit. for environ. Protection at the Council of Ministers of the People's Republic of Bulgaria. Пресс.
Чикаго маягийн жагсаалтDyulgerov N. Nature Protection Is a Social Necessity: Chairman of the Commit. for Environ. Protection at the Council of Ministers of the People's Republic of Bulgaria. София: Пресс, 1989.
MLA ишлэлDyulgerov N. Nature Protection Is a Social Necessity: Chairman of the Commit. for Environ. Protection at the Council of Ministers of the People's Republic of Bulgaria. Пресс, 1989.
Warning: These citations may not always be 100% accurate.