Murphy J R, Baqar S, Muñoz C, Schlesinger L, Ferreccio C, Lindberg A A, Svenson S, Losonsky G, Koster F, Levine M M
Department of Medicine, University of Maryland School of Medicine, Baltimore 21202.
J Infect Dis. 1987 Dec;156(6):1005-9. doi: 10.1093/infdis/156.6.1005.