What masterpieces of calligraphy did Dong Qichang write between 40 and 60?

If Dong Qichang's extensive knowledge of calligraphy is accumulated before the age of 40, then the period from 40 to 60 is his development stage of learning from the ancients and learning from others. During this period, he studied under 100 ancient masters. Among them, the calligraphy of Su Shi and Mi Fei in Song Dynasty gave him great enlightenment, especially the natural ancient rhyme of Mi Fei fascinated him. With the deepening of ancient studies, Dong Qichang's works began to enrich gradually. The representative works of this period, such as Gu Lin Volume, Gui Mao Cao Xing Volume, Gui Mao Lin Miscellaneous Volume, Liu Tang Zongyuan Poetry, Wang Xizhi's Postscript, Imitation of Huai Su Style Book, etc., are mainly cursive, which are both ancient and creative. Among them, the Tang Dynasty's imitation of Huai-Su style calligraphy poems has a beautiful ending, which is shaped by the situation and full of fun, and has shown the unique cursive style of Dong Shi.