Spectroscopy: Infrared and FT-IR

Hanneman, W., and Hintze, R. “Gum Characterization by Infrared Spectroscopy,” The American Philatelist, Vol. 105, No. 9, September 1991, pp. 816-817.
Lera, T.
“In the National Postal Museum, Research: Scientific Equipment at the NPM,” The Collectors Club Philatelist, Vol. 91, No. 3, May-June 2012, pp. 174-178.
Poslusny, M., and Daugherty, K.E. “A Novel Approach to Looking at Stamps,” The American Philatelist, Vol. 104, No. 8, August 1990, pp. 722-726.