00467nam a2200145 a 450000500170000000800410001702000180005804100080007608200100008410000210009424501070011525000120022226400610023430000260029520260717092731.0260717s2009    ii            000 0 eng d  a9780763751616  aeng04a614.41 aFriis, Robert H.10aEpidemiology For Public Health Practice :bEpidemiology For Public Health Practice /cFriis, Robert H.  a4th ed. 1aSudbury, Mass :bJones and Bartlett Publishers,cc2009,.  axxii, 717 p. ; 23 cm.