1. A note on the eliminative behaviour of groups of castrated male pigs. CIGR Section II;Baxter,1977
2. Beitrage zur zweikomponenten Theorie des Hungers;Bayer;Z. Psychol.,1929
3. Social dominance in swine;Beilharz;Anim. Behav.,1967
4. Frustration and Aggression;Dollard,1939
5. Social environment of the pig;Ewbank,1971