APA (7th ed.) Citation

Varkonyi, R. (2012). Drupal Rules How-To. Packt Pub.

Chicago Style (17th ed.) Citation

Varkonyi, Robert. Drupal Rules How-To. Birmingham: Packt Pub, 2012.

MLA (9th ed.) Citation

Varkonyi, Robert. Drupal Rules How-To. Packt Pub, 2012.

Warning: These citations may not always be 100% accurate.