RT Journal Article T1 Vũ Ngọc’s conjecture on focus-focus singular fibers with multiple pinched points A1 Pelayo, Álvaro A1 Tang, Xiudi PB Birkhäuser SN 1661-7738 SN 1661-7746 YR 2024 FD 2024 LK https://hdl.handle.net/20.500.14352/129210 UL https://hdl.handle.net/20.500.14352/129210 LA eng NO Pelayo, Á., Tang, X. Vũ Ngọc’s conjecture on focus-focus singular fibers with multiple pinched points. J. Fixed Point Theory Appl. 2024 Jan 25;26 (6). DS Docta Complutense RD 17 mar 2026