Ward, Porter Elwood creator Truxes, L. S. text dcu Washington, D. C U. S. Geological Survey 1964 monographic 248 p. ill. by P. E. Ward and L. S. Truxes ; prepared by the United States Geological Survey in cooperation with The Legislative Assembly of Puerto Rico...[et al.] Water, Under ground Puerto Rico 941214 20160527191525.0 189704