TY - JOUR T1 - The use of Protozoa to indicate changes in the performance of activated-sludge plants. JF - Water Research. Y1 - 1991 A1 - Al-Shahwani, S. M. A1 - Horan, N. J. SP - 633 EP - 638 VL - 25 N1 - Records, Ecol., Indicators ER -