The Normal Family Related To Shared A Value

In the paper we considered that T is a family of functions in a domain D, Let k>2 be a posi-tive integerand and b a nonzero constant. for any function f∈F, the zero of f(z) have multiplicity at least k. f(z)f(k)(z)=z2(?)f(k)(z)=b, then F is normal in D.