Inside back cover mentions that "Mister X is based upon the character created by Dean Motter and additional concepts by Paul Rivoche."
ISBN given in indicia as 0-921451-06-7 but that appears to have been officially registered to another book published by Vortex (Highway 61 Revisited). Worldcat info for this book at http://www.worldcat.org/title/mister-x-special/oclc/52215596 .
Title from inside front cover.
On back cover of comic.