00414nam a22001217a 4500008004100000020001500041040005500056080002100111245010800132260002600240300001400266650001200280230612b        |||||||| |||| 00| 0 eng d  a9241544716  aNational Science LibrarycNational Science Library  a628.1(1-21) bN4  aOperation and maintainence of urban water supply and sanitation systems: bA guide for managers c/ WHO  aGeneva: bWHO, c1994  aix, 102p.  aScience