We define natural \ainf-transformations and construct \ainf-category of \ainf-functors. The notion of non-strict units in an \ainf-category is introduced. The 2\n-category of (unital) \ainf-categories, (unital) functors and transformations is described.
Homology, Homotopy and Applications, Vol. 5(2003), No. 1, pp. 1-48