Thought you might like this. It's the textbook for Columbia's intermediate Korean course.
Textbook: Integrated Korean, Intermediate 1 and 2.
Young-Mee Cho, Hyo Sang Lee, Carol Schulz, Ho-Min Sohn, Sung-Ock Sohn.
Hawaii: Univ. of Hawaii Press. 2000
Workbook: Integrated Korean Workbook, Intermediate 1.
Carol Schulz. Hawaii: Univ. of Hawaii Press. 2001
Integrated Korean Workbook, Intermediate 2. Hawaii: Univ. of Hawaii Press. 2001