Rights to 80's cartoon characters can anybody help

[truereddevil]

Hi i am new to this forum and i deal in retro type t-shirts within the uk i was and still am a big fan of the 80's cartoons some of my faves were he-man,thundercats,bravestarr,visionairies,centurians,ewoks,mask and knightmare and now i am looking too branch out on my t-shirts by getting some of the classic 80's cartoon characters onto t-shirts does anybody know where i could even start with this to speak to the holders of the licenced characters