Gaya APA

Ulrich, W, M., Hayes, I, S. (1997). The Year 2000 software crisi : challenge of the century . Upper Saddle River, NJ: Prentice Hall.

Gaya MLA

Ulrich, William, M.., Hayes, Ian, S.. "The Year 2000 software crisi : challenge of the century". Upper Saddle River, NJ: Prentice Hall, 1997. Text.