1. Antisera from Seward Lab., UAC House, Blackfriars Road, London SEI 9UG, and Kallestad Labs Inc., 1000 Lake Hazeltine Drive, Chaska, Minn. 55318, were all found suitable and each has kindly donated 100 ml of each class to the IFCC.
2. Ekins R.P.: Basic concepts in quality control - In: Radioimmunoassay and related procedures in medicine. Int. Atomic Energy Agency, Vienna, 1978; vol. 3, p. 6.
3. Hobbs J. R., Harboe N., Alper C., Johansson B. G.: The human serum standard IFCC 74/1 - Clin. chim. Acta98, 1979. (In press).
4. Mancini G., Carbonara A. O., Heremans J. F.: Immunochemical quantitation of antigens by single radial immunodiffusion - Immunochemistry 2, 235, 1965.
5. Rowe D. S., Anderson S. G., Grab B.: A research standard for human serum immunoglobulins IgG, IgA and IgM - Bull. Wld Hlth Org.42, 535, 1970.