Hauptmann, G., Dörner, K.-H., Hocker, H., and Pfisterer, G., Cellular and Non-Cellular PolyurethanesInternational Conference Strasbourg, France, 1980, Carl Hanser Verlag, München / Wien, p. 617 (1980).
2.
Rossmy, G., Kollmeier, H. J., Lidy, W., Schator, H., and Wieman, M., loc. cit, p. 635.