DEVELOPMENTS IN BIOLOGICAL 525,919 STANDARIZATION vol.30. International Symposium on Viral Hepatitis Proceedings of the 44th Symposium organized by the International Association of Biological Standardisation and held at The Congress Hall,Via Corridoni,Milan,Italy 16-19 December 1974.Acting ed. R.H.Regamey, W.Hennessen and F.T. Perkins. Basel 1975 S.Karger 8° s. 2.490, nlb. 4,il. International Association of Microbiological Societies Developments in Biological Standardization vol. 30