I am reading Father Willem Grootaers' research on Chinese religion in Xuanhua 宣化, Wanquan 万全, and Datong 大同 recently. He was a linguistic geographer working in China before 1945 and later moved to Japan. His method greatly influenced Japanese linguist geographers and he won a medal from the Japanese emperor (Orders of the Sacred Treasure 三等瑞宝章). There is no entry on him and his complete work in English. The following sources may say a lot about his life.
Works in Dialectology by Reverend Willem A. Grootaers
by Fumio Inoue
http://innowayf.net/download/Works_in_Dialctology_by_Reverend_Grootaers.pdf
Wikipedia entry in Japanese
Below are two of his popular books in Japanese.
