| http://www.w3.org/ns/prov#value | - wherein M1 and M2 are independently a valence bond, --O-- or --NH--, R1 ' is a valence bond, a group of the formula ##STR21## with the proviso that--if R1 ' is a valence bond--only one of M1 and M2 can be --O--, R2 ' and R3 ' are independently ##STR22## the aryl radicals R1 ', R2 ' and R3 ' are optionally substituted by alkyl of 1 to 4 carbon atoms, R4 is a valence bond, --O--, alkylene of 1 to 4
|
