International Federation of Clinical Chemistry. Committee on Standards. Expert Panel on Enzymes. Approved recommendation (1978) on IFCC methods for the measurement of catalytic concentration of enzymes. Part 1. General considerations concerning the determination of the catalytic concentration of an enzyme in the blood serum or plasma of man - Bowers, GNJ; Bergmeyer, HU; Horder, M; Moss, DW (Clin Chim Acta, 1979)