1. Martini JE. The production and analysis of microcellular foam. SM thesis. Dept. Mech. Eng, MIT; 1981.
2. Handbook of foaming and blowing agents: introduction: lessons from living things;Wypych,2017
3. Hermann H, Virginia L, Timothy M, Heike K, Jackie S, Mark L. Impregnating solution for cosmetic cloths, patent, US; 2006.
4. Williams RS. Ethafoam and other polyethylene foams in conservation, patent, Canada; 1998.
5. Helen CM. Photographic film and a laminated protective coating therefor, patent, US; 1933.