Stookey, J. M.; Gonyou, H. W. (1998). "Recognition in swine: recognition through familiarity or genetic relatedness?". Applied Animal Behaviour Science. 55 (3–4): 291–305. doi:10.1016/S0168-1591(97)00046-4.
Orlove, M. J. (1979). "A Reconciliation of Inclusive Fitness and Personal Fitness Approaches: a Proposed Correcting Term for the Inclusive Fitness Formula". Journal of Theoretical Biology. 81 (3): 577–586. Bibcode:1979JThBi..81..577O. doi:10.1016/0022-5193(79)90055-9. PMID537387.
Orlove, M. J. (1979). "A Reconciliation of Inclusive Fitness and Personal Fitness Approaches: a Proposed Correcting Term for the Inclusive Fitness Formula". Journal of Theoretical Biology. 81 (3): 577–586. Bibcode:1979JThBi..81..577O. doi:10.1016/0022-5193(79)90055-9. PMID537387.
Orlove, M. J. (1979). "A Reconciliation of Inclusive Fitness and Personal Fitness Approaches: a Proposed Correcting Term for the Inclusive Fitness Formula". Journal of Theoretical Biology. 81 (3): 577–586. Bibcode:1979JThBi..81..577O. doi:10.1016/0022-5193(79)90055-9. PMID537387.