1. The free surface around, and the interference between, gravity wells;Babbitt,1948
2. Evaluation of unconfined flow to multiple wells by the membrane analogy;Hansen,1949
3. Unconfined ground-water flow to multiple wells;Hansen;Proc. Amer. Soc. Ci Eng.,1952
4. Flow of ground water, Chap. 5;Jacob,1950
5. Muskat, M., , The flow of homogeneous fluids through porous media, J. W. Edwards, Ann Arbor, Michigan, 1946,