Il'yasov Y., Runst T., “On nonlocal calculation for inhomogeneous indefinite Neumann boundary value problems”, Calculus of Variations and Partial Differential Equations, 22:1 (2005), 101–127
Il'yasov Y., Runst T., “Nonlocal investigations of inhomogeneous indefinite elliptic equations via variational methods”, Function Spaces, Differential Operators and Nonlinear Analysis: the Hans Triebel Anniversary Volume, 2003, 341–352
Я. Ш. Ильясов, “Нелокальные исследования бифуркаций решений нелинейных эллиптических уравнений”, Изв. РАН. Сер. матем., 66:6 (2002), 19–48 ; Ya. Sh. Il'yasov, “Non-local investigation of bifurcations of solutions of non-linear elliptic equations”, Izv. Math., 66:6 (2002), 1103–1130