1. Natural Varnish Resins;Barry,1932
2. Spectroscopic investigations of amber;Beck;Appl. Spectrosc. Rev.,1986
3. Is the air in amber ancient?;Beck;Science,1988
4. The infrared spectra of amber and the identification of Baltic amber;Beck;Archaeometry,1965
5. The characterization of Lat Cretaceous (Campanian-Maastrichtian) fossil resin from the Fossil Forest Study Area, San Juan Basin, New Mexico;Bellis,1990