1. See e.g. G USP2 149 051 (1935); IG French P789 950 (1934);BP440 113 (1934);German P639 727 (1936);German P644 724 (1937).
2. Eastman Kodak Co. BP744 877 (1953);USP2 785 157 (1952).
3. See e.g. BASF BP810 736 (1956); S BP819 664 (1956); ICI BP953 887 (1960).
4. ICI BP859 899 (1958);BP859 900 (1958).
5. S BP851 910 (1958);