The author discusses fixed point theorems for operators T in a Banach space satisfying \[ \| Tx-Ty\| \leq a\| x-y\| +b\| x- Tx\| +b\| y-Ty\| +c\| x-Ty\| +c\| y-Tx\|. \] Related results are due to W. R. Derrick and L. Nova G. [see the preceding review].