The main aim of this paper is to obtain fixed point theorems
for Kannan and Zamfirescu operators in the presence of cyclical contractive
condition. A method for approximation of the fixed points is also provided,
for which both a priori and a posteriori error estimates are given. Our results
generalize, unify and extend several important fixed points theorems in literature. In order to illustrate the efficiency of our generalizations five significant examples are also given.
