TY - BOOK AU - Gordis,Leon TI - Epidemiology SN - 0721603262 AV - RA651 .G58 2004 U1 - 614.4 21 PY - 2004/// CY - Philadelphia, Pa. PB - Saunders KW - Epidemiology KW - Epidemiologic Methods N1 - Includes bibliographical references and index ER -