http://robknight.org.uk/blog/2011/02/explaining-architectural-tiers-drupal/
http://www.ciss100.com/lecture-topics-modules/database/3-tier-web-architecture/case-study-drupal-cms/
Coding, Software and Tech Reviews
http://robknight.org.uk/blog/2011/02/explaining-architectural-tiers-drupal/
http://www.ciss100.com/lecture-topics-modules/database/3-tier-web-architecture/case-study-drupal-cms/