Williams, George C. (November 1966). "Natural Selection, the Costs of Reproduction, and a Refinement of Lack's Principle". The American Naturalist. 100 (916): 687–690. doi:10.1086/282461. JSTOR2459305.
Pasztor, E.; Loeschcke, V. (November 1989). "The Coherence of Cole's Result and Williams' Refinement of Lack's Principle". Oikos. 56 (3): 416–420. doi:10.2307/3565627. JSTOR3565627.
jstor.org
Williams, George C. (November 1966). "Natural Selection, the Costs of Reproduction, and a Refinement of Lack's Principle". The American Naturalist. 100 (916): 687–690. doi:10.1086/282461. JSTOR2459305.
Pasztor, E.; Loeschcke, V. (November 1989). "The Coherence of Cole's Result and Williams' Refinement of Lack's Principle". Oikos. 56 (3): 416–420. doi:10.2307/3565627. JSTOR3565627.