TY  - BOOK
AU  - Helmer, Richard,
AU  - Hespanhol, Ivanildo.
ED  - United Nations Environment Programme.
ED  - Water Supply and Sanitation Collaborative Council.
ED  - World Health Organization.
TI  - Water pollution control: a guide to the use of water quality man agement principles 
SN  - 0419229108
U1  - 363.739/4  21
PY  - 1997///
CY  - London,  New York
PB  - E & FN Spon
KW  - Water quality management
KW  - Water
KW  -  Purification
N1  - "Published on behalf of UNEP, United Nations Environment Program, Wa ter Supply & Sanitation Collaborative Council, World Health Organizatio n."; Includes bibliographical references and index
ER  -