Pejsachowicz J. Index bundle, Leray-Schauder reduction and bifurcation of solutions of nonlinear elliptic boundary value problems. TMNA [Internet]. 2001 Dec. 1 [cited 2024 Apr. 19];18(2):243-67. Available from: https://apcz.umk.pl/TMNA/article/view/TMNA.2001.033