The figure contained in the article "Choosing the Right Refrigerant" contains information copyrighted by James M. Calm in 1995. The information was first published in 1997 in a paper, "Trade-Offs in Refrigerant Selections: Past, Present and Future," presented by Calm and David A. Didion to the ASHRAE/NIST conference, "Refrigerants for the 21st Century."