Siverson, Randolph, y Hayward R Alker. 1975. «Hayward R. Alker Jr. Et Al. Mathematical Approaches to Politics. Amsterdam : Elsevier Scientific Publishing Company, 1973. 475 P». Foro Internacional 15 (4). México, Ciudad de México:638-40. https://forointernacional.colmex.mx/index.php/fi/article/view/703.