Não informado. (2020). Progress Report of the Bulgarian National Committee for the International Biological Programme. Bulgarian National Committee for the International Biological Programme.
Chicago-Zitierstil (17. Ausg.)Não informado. Progress Report of the Bulgarian National Committee for the International Biological Programme. Sofia: Bulgarian National Committee for the International Biological Programme, 2020.
MLA-Zitierstil (8. Ausg.)Não informado. Progress Report of the Bulgarian National Committee for the International Biological Programme. Bulgarian National Committee for the International Biological Programme, 2020.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.