Richardson, R.G.D. (1918) Contributions to the Study of Oscillation Properties of the Solutions of Linear Differential Equations of the Second Order. American Journal of Mathematics, 40, 283-316.
http://dx.doi.org/10.2307/2370485

has been cited by the following article:

• TITLE: On a Non-Definite Sturm-Liouville Problem in the Two-Turning Point Case—Analysis and Numerical Results

  AUTHORS: Mervis Kikonko

  KEYWORDS: Eigenvalue, Eigenfunction, Non-Definite, Turning Point, Richardson Number, Richardson Index, Haupt Index, Oscillation Number, Right-Definite, Left-Definite

  JOURNAL NAME: Journal of Applied Mathematics and Physics, Vol.4 No.9, September 28, 2016

  ABSTRACT: In this paper, we study the non-definite Sturm-Liouville problem comprising of a regular Sturm-Liouville equation and Dirichlet boundary conditions on a closed interval. We consider the case in which the weight function changes sign twice in the given interval of definition. We give detailed numerical results on the spectrum of the problem, from which we verify various results on general non definite Sturm-Liouville problems. We also present some theoretical results which support the numerical results. Some numerical results seem to be in contrast with the results that are so far obtained in the case where the weight function changes sign once. This leads to more open questions for future studies in this particular area.