1. D. N. Bethune, 1991 . Field and modeling studies of contamination of Laguna Asososca, Managua, Nicaragua . M.Sc. thesis, Univ. of Waterloo, Waterloo, Canada. 105 pp.
2. F. G. Driscoll, 1986 . Groundwater and Wells . Johnson Division, St. Paul, MN. 1089 pp.
3. A. Freeze, and J. Cherry . 1979 . Groundwater . Prentice-Hall, Englewood Cliffs, NJ. 604 pp.