Here is a 2011 book edited by Wonsuk Ma and Hun Kim for Regnum books.
Order from the Publisher: http://www.ocms.ac.uk/regnum/detail.php?book_id=71
Publisher Description: As a ‘divine conspiracy’ for Missio Dei, the global phenomenon of people on the move has shown itself to be invaluable. In 2004 two significant documents concerning Diaspora were introduced, one by the Filipino International Network and the other by the Lausanne Committee for World Evangelization. These have created awareness of the importance of people on the move for Christian mission. Since then, Korean Diaspora has conducted similar research among Korean missions, resulting in this book. It is unique as the first volume researching Korean missions in Diasporic contexts, appraising and evaluating these missions with practical illustrations, and drawing on a wide diversity of researchers.