Orbital Period Variations in HT Cas: Evidence for Additional Angular Momentum Loss and a High-eccentricity Giant Planet oleh Z.-T Han, S.-B Qian, Q.-W Han, L. Zang, B. Soonthornthum, L.-J Li, L.-Y. Zhu, W. Liu, E. Fernández Lajús, Z.-B Dai, W.-W Na