EPA -Washington, DC, US,
“National conference on less costly wastewater treatment systems for small communities : a compilation of papers presented at the USEPA National Conference, held at Reston, Virginia, on April 12, 13, and 14, 1977”, vol. 600979010. US Environmental Protection Agency (EPA), Reston, VA, USA, p. 118 pp. : fig., tab. ref., 1978.
J. Walsh and EPA -Washington, DC, US,
“Process design manual : municipal sludge landfills”, vol. EPA/625/1-78/010. US Environmental Protection Agency (EPA), Washington, DC, USA, p. Various paging : tab. fig., 1978.