Σύνδεσμος php.net
The language that Joomla! is developed in
Σύνδεσμος MySQL
The database that Joomla! uses
Σύνδεσμος Ohloh Tracking of Joomla!
Objective reports from Ohloh about Joomla's development activity. Joomla! has some star developers with serious kudos.