Helleborus Niger: Systematics, Ecology, Pollination and Production Technology. [s.l.] : Univerzitetna založba Univerze v Mariboru,2021. DOI: 10.18690/978-961-286-483-5. Disponível em: https://press.um.si/index.php/ump/catalog/book/580.. Acesso em: 18 may. 2024.