Here are references that include more general information on the NACA era and aircraft icing.

Lew Rodert, Epistemological Liaison, and Thermal De-Icing at Ames

"We Freeze to Please": A History of NASA's Icing Research Tunnel and the Quest for Flight Safety

"Bringing the Future Within Reach: the NASA John H. Glenn Research Center"

"The Wind and Beyond: Journey into the History of Aerodynamics in America, Volume 2, Reinventing the Airplane.", NASA-SP-4409, 2007. (Especially the "Heat Against Ice" excerpt, p. 506-518.)
history.nasa.gov