1. Respiratory Protective Devices;
Final Rules and Notice,
as printed in Federal Register 60(110); Title 42 Code of Federal Regulation
Part 84, June 8, 1995; pp 30336–30404.
2. Personal
telephone conversation with Phil Eitzman of 3M on 11/21/2019.
3. The Effects of Particle Charge on the Performance of a Filtering Facepiece
4. van Turnhout, J. Method for the Manufacture of an Electret Fibrous Filter. U.S. Patent US3,998,916, December 21, 1976.