Pathak, A. , Dastidar, M. , Sreekrishnan, T.. "Bioleaching of Heavy Metals from Sewage Sludge Using Indigenous Iron-Oxidizing Microorganisms: Effect of Substrate Concentration and Total Solids". World Academy of Science, Engineering and Technology, Open Science Index 34, International Journal of Environmental and Ecological Engineering, (2009), 3(10), 326 - 331.