He also was given the permanent title of visiting professor by Rockefeller University in 1966 and he spent several years there working both with geneticists and mathematicians while on leave from Princeton.
Siya rin ay bibigyan ng permanenteng titulo ng mga propesor sa pamamagitan ng pagbisita sa Rockefeller University in 1966 at siya na ginugol ng ilang taon na may parehong nagtatrabaho sa geneticists at mathematicians habang on leave mula sa Princeton.