Groot, B. d. (1961). Libido and semen characteristics of bull twins with special regard to genotypic and environmental variability. G. van Dijk.
Chicago-viite (17. p.)Groot, Bram de. Libido and Semen Characteristics of Bull Twins with Special Regard to Genotypic and Environmental Variability. Breukelen: G. van Dijk, 1961.
MLA-viite (8. p.)Groot, Bram de. Libido and Semen Characteristics of Bull Twins with Special Regard to Genotypic and Environmental Variability. G. van Dijk, 1961.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.