@article{leaf_1967, 
  title={Errata to: ''An approximation theorem for a class of operators"}, 
  volume={18}, 
  DOI={10.1090/s0002-9939-1967-0216325-x}, 
  publisher={American Mathematical Society (AMS)}, 
  author={Leaf}, 
  year={1967}, 
  month={Jun}
  }