Calligraphie Wang, Xizhi 王羲之 Sun, Guoting 孫過庭 Jìn Táng fǎshū zhōng de jié bǐ xiànxiàng yǔ zhézhǐ wénhuà 晉唐法書中的節筆現象與摺紙文化 = Bamboo Joint Strokes in the Calligraphy of the Jin and Tang Dynasties