We consider the nonlinear equation t^2x'' + g(x) = 0, where g(x) satisfies xg(x) > 0 for x \ne 0, but is not assumed to be sublinear or superlinear. We study the problem whether all nontrivial solutions of the equation are oscillatory in some critical cases.
AGHAJANI, ASADOLLAH and ROOMI, VAHID
"An oscillation theorem for second-order nonlinear differential equations of Euler type,"
Turkish Journal of Mathematics: Vol. 36:
2, Article 8.
Available at: https://journals.tubitak.gov.tr/math/vol36/iss2/8