Pečiulytė, S., Štikonienė, O. and Štikonas, A. (2008) “Investigation of Negative Critical Points of the Characteristic Function for Problems with Nonlocal Boundary Conditions”, Nonlinear Analysis: Modelling and Control, 13(4), pp. 467–490. doi:10.15388/NA.2008.13.4.14552.