In this paper we study the problem of normal families of meromorphic functions concerning shared values. Let F be a family of meromorphic functions in the plane domain D subset of C and it be a positive integer. Let a, b be two finite complex constants such that a not equal 0. If n >= 3 and f + a(f')(n) and g + a(g')(n) share b in D for every pair of functions f, g is an element of F, then F is normal in D. And some ...
