I came across two very informative research papers on the Korean minority in NE asia (outside of the Korean peninsula), both published by Korean universities in English.


Ethnic Korean Migration in Northeast Asia
http://gsti.miis.edu/CEAS-PUB/200108Lee.pdf

html version (formatted less well): http://tinyurl.com/25ccq4



The Korean Minority in China: Change of Its Identity
http://sociology.snu.ac.kr/isdpr/publicati...i%20Woo-Gil.pdf

html version (formatted less well): http://tinyurl.com/2c7h3k



Ethnic-Korean Returnees in the Russian Far East
http://www.cct.go.kr/data/acf2006/multi/mu...young%20Lee.pdf

html version: http://tinyurl.com/2mtutd



This paper documents three four Korean ethnic groups (as well as other East Asian ethnic groups) in Russia, and the relationships between the them:
Korean Chinese, Korean Russians, DPRK Koreans, and ROK Koreans, with emphasis on the economically most important group, the Korean-Chinese.

Korean-Chinese Migration into Russia
http://src-h.slav.hokudai.ac.jp/coe21/publ...hapter5_lee.pdf

html version: http://tinyurl.com/2e8hnt