1. Some recent economic and scientific questions in ornithology Author(s): Shufeldt, Robert W. (Robert Wilson), 1850-1934 author Publication: New York : N.D.C. Hodges, 1893 Subject(s): BirdsPopulation DensityUnited States
2. On the present status of Passer domesticus in America, with special reference to the western states and territories Author(s): Coues, Elliott, 1842-1899 author Publication: Washington : [published not identified], September 6, 1879 Subject(s): SparrowsPopulation DensitySouthwestern United StatesNorthwestern United States