APA

Whitney N., . (1992). The Sky's the Limit. Oxford: Heinemann ELT.

Chicago

Whitney N, . 1992. The Sky's the Limit. Oxford: Heinemann ELT.

Harvard

Whitney N., . (1992). The Sky's the Limit. Oxford: Heinemann ELT.

MLA

Whitney N, . The Sky's the Limit. Oxford: Heinemann ELT. 1992.