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. Countdown to collision Publication: [Airlie, Va.?] : George Washington University, [1972] Subject(s): Environmental PollutionEnvironmentPopulation DensityUnited States
3. 1 + 1 = 5 Publication: [United States? : s.n., 19--?] Subject(s): Population GrowthPopulation DensityFamily CharacteristicsUnited States
