E. A. Evans et al . , J. Label. Compounds , 10 , 4 , 569 ( 1974 ).

E. A. Evans , Tritium and its Compounds , 2nd ed. , London , Butterworths , 1974 ,P. 310 .

O Bucoman et al . , J. Label. Compounds , 10 2 , 345 ( 1974 ).

I. Pri-Bar and O. Buchman , Int. J . Appl. Radia. Isotop. , 27 53 ( 1976 ).