APA

Stephen Haag, Maeve Cummings, . (2009). Information Systems Essentials. Boston: McGraw Hill Irwin.

Chicago

Stephen Haag, Maeve Cummings, . 2009. Information Systems Essentials. Boston: McGraw Hill Irwin.

Harvard

Stephen Haag, Maeve Cummings, . (2009). Information Systems Essentials. Boston: McGraw Hill Irwin.

MLA

Stephen Haag, Maeve Cummings, . Information Systems Essentials. Boston: McGraw Hill Irwin. 2009.