American-Mexican boundary cooperation : hearing, Ninety-second Congress, second session on H.R. 10623, relating to measures for solution of the lower Rio Grande Salinity problem; H.R. 10624, relating to emergency flood control works on the lower Colorado River and H.R. 14573, a bill to facilitate compliance with the new United States-Mexican Boundary Treaty, May 1, 1972. (U.S. Govt. Print. Off, 1972)