Grange, J.M., Gibson, J., Nassau, E. and Kard-jito, T. (1980) Enzyme-linked immunosorbent assay (ELISA): A study of antibodies to Mycobacterium tuberculosis in the IgG, IgA and IgM classes in tuberculosis, sarcoidosis and Crohn’s disease. Tubercle, 61, 145-152.