538,083 MICROENVIRONMENTS Microenvironments in haemopoietic and lymphoid differentiation. Symposium on.... held at the Ciba foundation, London 11—13 November 1980 In honour of Professor John Humphrey Ed-s: Ruth Porter and Julie Whelan. London 1981 Pitman 8° s. XI, nlb. 1, 348, il. Ciba Foundation Symposium 84