1. Schade G, (to Dynamit Nobel AG, Fed. Rep. of Germany) US Patent 4104262, Aug. 1, 1978.
2. Kibler ChJ, GR Lappin, JM Hawkins and WC Wooten Jr., (to Eastman Kodak Co. Ltd.) US Patent 3546008, May 27, 1968; C.A.,71, 82295c
3. Baumann H, B Joos and W Funke,Makromol. Chem.,190, 83, 1989
4. Kotera N, Y Mizumara and H Miyake, (to Toyo Boseki Kabushiki Kaisha), US Patent 4340519, Jul. 20, 1982
5. Kotera N and K Takahashi,Bull. Chem. Soc. Jpn,.63, 2288, 1990