research papers
The standard-test tables of values of transmission factors and , the absorption-weighted mean path lengths, given by Cahen & Ibers [J. Appl. Cryst. (1972), 5, 298-299; J. Appl. Cryst. (1973), 6, 244] and Alcock [Acta Cryst. (1974), A30, 332-335] have been corrected and extended.