Yuji, Yuji. “Multiple Positive Solutions to Mixed Boundary Value Problems for Singular Ordinary Differential Equations on the Whole Line”. Nonlinear Analysis: Modelling and Control 17, no. 4 (October 25, 2012): 460–480. Accessed April 21, 2025. https://www.zurnalai.vu.lt/nonlinear-analysis/article/view/14051.