Walker, E., & Elsworth, S. (1991). Blueprint intermediate. Workbook. Longman.
Chicago Style (17th ed.) CitationWalker, Elaine, and Steve Elsworth. Blueprint Intermediate. Workbook. Harlow: Longman, 1991.
MLA (9th ed.) CitationWalker, Elaine, and Steve Elsworth. Blueprint Intermediate. Workbook. Longman, 1991.