On positive solutions of equations with two middle terms Witold A. Kosmala; William C. Bauldry — 1990 Annales Polonici Mathematici
Oscillation of a forced higher order equation Witold A. J. Kosmala — 1994 Annales Polonici Mathematici We state and prove two oscillation results which deal with bounded solutions of a forced higher order differential equation. One proof involves the use of a nonlinear functional.