 He then went on with his doctoral degree at the same university, studying under amongst others John Maynard Smith the University of Sussex, still working mostly on the theoretical aspects of evolution and ecology.Major publications from this period is his work on the Red Queen Hypothesis (Van Valen, 1973; Stenseth, 1979; Stenseth and Maynard-Smith, 1984) in addition to his work on population cycles of the Norwegian lemming.A dr.philos.