TY - BOOK AU - Barker,D.J.P. AU - Bennett,F.J. TI - Practical epidemiology SN - 0443023034 (pbk.) U1 - 614.40723 23 PY - 1982/// CY - Edinburgh, New York PB - Churchill Livingstone KW - Epidemiology KW - Technique N1 - Bibliography and index ER -