Investigation of the pollution and sanitary conditions of the Potomac watershed : with special reference to self purification and the sanitary condition of shellfish in the lower Potomac River / by Hugh S. Cumming. Plankton studies / by W.C. Purdy; and Hydrographic studies / by Homer P. Ritter.
Cumming, Hugh S. (Hugh Smith), 1869-1948. | Date: 1916