1. (a) J.R. Caldwell, R. Gilkey, US Patent 2,891,930 (1959)
2. (b) C.J. Kibler, A. Bell, J.G. Smith, US Patent 2,901,466 (1959); both to Eastman Kodak;
3. B.R. Patel, G.F. Smith, T.E. Banach, US Patent 5,986,040 (1999, to GE).
4. Segmented copolymers with poly(ester amide) units of uniform length: synthesis