@robstefanei just started to read "Programming Microsoft Dynamics NAV 2013"
http://www.packtpub.com/programming-microsoft-dynamics-nav-2013/book
by David A. Studebaker, Christopher D. Studebaker
A comprehensive reference for development in Microsoft Dynamics NAV 2013, with C/SIDE and C/AL
Brimming with detailed documentation that is additionally supplemented by fantastic examples
The perfect companion for experienced programmers, managers and consultants