Cita APA (7a ed.)

Richards, R. (2006). Pro PHP XML and web services. [S.n.].

Cita Chicago Style (17a ed.)

Richards, Robert. Pro PHP XML and Web Services. Berkeley: [S.n.], 2006.

Cita MLA (9a ed.)

Richards, Robert. Pro PHP XML and Web Services. [S.n.], 2006.