<p>Where can I find a complete reference of the ncurses C API?</p>

You can buy this book. I have it and recommend: John Strang, Programming with curses, O'Reilly, ISBN 0-937175-02-1
The best online source information:
http://invisible-island.net/ncurses/ncurses-intro.html
I learned a lot about ncurses reading the minicom source code and the iptraf linux network monitor.