7Carpentier P J.method of producing light and resistant cellular bodies, US2576749,1951-11-27.
8Jagadish C.Goswami, et al.process for forming a crosslinked polyvinyl chloride foam and product thereof by means of radiation crosslinking, US4187159, 1980-02-05.
9Georg G.A.Bohm, et al.radiation crosslinked polyvinyl chloride and process therefor, US3998715,1976-12-21.
10Haruki Kakitani, et al.process for preparing a highly expanded polyvinyl chloride foam product, US4028449.1977-06-07.