1. Si queremos avanzar--: tenemos que estar bien distribuidos Publication: Lima, Peru : Consejo Nacional de Población, [19--?] Subject(s): Population ControlPopulation DensityPeru
2. 1 + 1 = 5 Publication: [United States? : s.n., 19--?] Subject(s): Population GrowthPopulation DensityFamily CharacteristicsUnited States
