1. Malik SK, Jenkins DE. Chest 1972;62:660-4.
2. ' Melville GN, Iravani;Allegra, L.; Bianco, S.;European J'ournal of Respiratory Diseases,1973
3. 'Ylikorkala 0, Viinikka L;Machin, S.J.; Defreyn, G.; Vermylen, J.;Br J Haematol,1981
4. Remuzzi G, Misiani R, Marchesi D Livio M, Mecca G, de Gaetano G. Lancet 1978;ii:871-2.