You can find out many information from History of the Mongols from the 9th to the 19th century by Henry H Howorth The Cambridge history of China Volume 2 ed Denis Crispin Twitchett John King Fairbank Christopher P Atwood Encyclopedia of Mongolia and the Mongol Empire Mongolia s culture and society by Sechin Jagchid The Jewel Translucent Sutra Altan Khan and the Mongols in the Sixteenth Century I like the first three best but it is just my opinion