“…These periodic solutions are of simple type, i.e., they have exactly one maximum per period. Analytic results (Walther, 1981a) and numerical simulations (Mackey and Glass, 1977;Hadeler, 1980;Saupe, 1982;Longtin and Milton, 1989a) support evidence that these periodic solutions are stable limit cycles. On the other hand, when f is a nonmonotone function, (3) can exhibit very complex dynamics including period-doubling bifurcations and chaos, as has been shown both numerically (Mackey and Glass, 1977;Glass and Mackey, 1979) and analytically (Peters, 1980;Walther, 1981b;an der Heiden and Mackey, 1982;an der Heiden and Walther, 1983).…”