Solutions of f ' ' + P ( z ) f = 0 that have almost all real zeros. Gundersen, Gary G. — 2001 Annales Academiae Scientiarum Fennicae. Mathematica
Solutions of nonhomogeneous linear differential equations with exceptionally few zeros. Gundersen, Gary G.; Steinbart, Enid M.; Wang, Shupei — 1998 Annales Academiae Scientiarum Fennicae. Mathematica
Existence of meromorphic solutions of algebraic differential equations. Ilpo Laine; Gary G. Gundersen — 1990 Mathematica Scandinavica