The topological A model was constructed by Witten in Comm. Math. Phys. Volume 118, Number 3 (1988), 411-449. I am looking for the original paper where topological B model was first introduced. I am reading another paper of Witten, Topological Field theory and mirror manifolds, where he discussed the B model, but I am looking for first construction of B model.
Can you also suggest some other references about the modern treatment of B model. I know Kevin Costello has done some work in this direction.