Current student Bijia Chen, former student Hao Dong and I recently published a paper in Demographic Research on ethnic intermarriage in Shuangcheng, Heilongjiang, during the late Qing:
https://www.demographic-research.org/volumes/vol38/34/
This paper grew out of Bijia’s MPhil thesis. It uses registered ethnicity of males and inferred ethnicity of wives to examine marriage between Han, Manchu, and others within the Banner populations in Shuangcheng in the late 19th century. Wife’s ethnicity was inferred from her surname. The population is a useful one to study because the Han, Manchu and others who composed it were all part of the Banners, and marriages between them were not subject to rules that forbade or discouraged marriage between Banners and non-Banners. In other words, it is an opportunity to study boundaries between Manchu and Han in a setting where they were not subject to regulations on Banner/non-Banner marriage that would have had the side effect of making Manchu/Han marriage difficult in most other parts of China.
The analysis uses the CMGPD Shuangcheng database, which is available for download from ICPSR:
https://www.icpsr.umich.edu/icpsrweb/ICPSR/studies/35292