1. Properties of solutions of u″ + g(t) u2n − 1 = 0;Utz;Monatsh. Mat.,1965
2. On the properties of the solutions of nonlinear differential equations of the second order;Faǐzibaev;Izvestija Akad. Nauk USSR, Ser. Phys.-Math.,1964
3. On second-order non-linear oscillation;Atkinson;Pacific J. Math.,1955
4. Extension of a theorem of Armellini-Tonelli-Sansone to the nonlinear equation u″ + a(t)f(u) = 0;Bihari;Magyar Tud. Akad. Mat. Kutató Int. Közl.,1962
5. On the nonlinear equation u″ + a(t) u + q(t)f(u2) = 0;Bihari;Magyar Tud. Akad. Mat. Kutató Int. Közl.,1961