“…There has been lots of activity in the discovery of exotic smooth structures on simply connected 4-manifolds with small Euler characteristic in the period of last 15 years. The following references are among many dealing with this subject [44,49,16,46,50,45,3,2,6,5,4,7,37,56,8,28]. In this article, we will be primarily interested in the construction of exotic smooth structures on simply connected 4-manifolds with small Euler characteristic using the rational-blowdown surgery [15,43].…”