Advancing Fluid Antenna-Assisted Non-Terrestrial Networks in 6G and Beyond: Fundamentals, State of the Art, and Future Directions. - Tianheng Xu; Runke Fan; Jie Zhu; Pei Peng 001; Xianfu Chen; Qingqing Wu 001; Ming Jiang; Celimuge Wu; Dusit Niyato; Kai-Kit Wong (CoRR, 2025)