Text: In May of 1998, according to Isikoff, when both he and Toobin had publishing deals, Toobin actually proposed over lunch that he and Isikoff join forces and co-author their Clinton books.
Entailment: Iskoff states that in 1998 he and Toobin planned on collaborating.
Contradiction: Iskoff and Tooblin have never cooperated with each other to write.