I am sorry to tell all of you this but, DBZ ended in 1997 and DBGT ended in 2001. Toriyama the creator was going to end DBZ with Frieza anyway but fans asked for more and when he ended DBZ he stopped writing it and just let the company do DBGT. There is no more DB episodes or books.
Well I guess nicktoons decided either DBZK and DBGT were not getting enough ratings or they wanted to open the slot for something less violent. But Dragon Ball Z finished a loooooong time ago, Kai that they show is actually a re-edited version that had a lot censored and cut out of it, including full episodes (albeit filler episodes).