Cita APA (7th ed.)

Zend Technologies & Herbert, S. (2005). Zend PHP certification study guide. Sams Pub..

Cita Chicago (17th ed.)

Zend Technologies i Stuart Herbert. Zend PHP Certification Study Guide. Indianapolis, Ind: Sams Pub., 2005.

Cita MLA (8th ed.)

Zend Technologies i Stuart Herbert. Zend PHP Certification Study Guide. Sams Pub., 2005.