1.
Farber M. Zeros of closed 1-forms, homoclinic orbits and Lusternik-Schnirelman theory. TMNA [Internet]. 2002 Mar. 1 [cited 2024 Jul. 3];19(1):123-52. Available from: https://apcz.umk.pl/TMNA/article/view/TMNA.2002.008