Historical theory mainly includes:
1. History of China's Calligraphy: 1) History of China's Calligraphy, seven volumes, waiting by Cong Wenjun, Jiangsu Education Press; 2) The History of Calligraphy in China, Volume I and Volume II, is written by Makita and Yu Cun, and published by People's Fine Arts Publishing House.
2. On Ancient Books: 1) Selected Calligraphy Papers of Past Dynasties, Shanghai Calligraphy and Painting Publishing House; 2) History of Calligraphy Criticism in China, written by Yujiro Nakata [Japan], Tianjin Ancient Books Publishing House.
The rest are basically self-made teaching materials or handouts, which are not so important to you.