1. Amber, Resinite, and Fossil Resins, Chapter 1;Langenheim,1995
2. Classification of amber based on thermal analysis;Ragazzi;Thermochim. Acta,2003
3. The Editors, Amber, fossil resin, Encyclopedia Brittanica, Last Updated: Sep 7, 2022. See also, The Properties of Amber, https://www.getty.edu/publications/ambers/intro/6/.
4. Amber: the organic gemstone;Lambert;Acc. Chem. Res.,2002
5. Thermal investigations of amber and copal;Feist;Thermochim. Acta,2007