Causas que impiden la protección del medio ambiente. by Quevedo S., Manuel M.

Subjects: “…CONSERVACION DE RECURSOS NATURALES…”

Problemas de conservación de algunos recursos naturales en Centroamérica. by Rodezno C., Eduardo

Subjects: “…CONSERVACION DE RECURSOS NATURALES…”

Protección del medio ambiente y de los recursos naturales en Perú. by Ferreira, Ramón

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Proceedings of second Pan American scientific congress : conservation and economic theory / by Ely, Richard T.

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Biodiversidad de Tucumán y el Noroeste argentino. Aportes de la Fundación Miguel Lillo a su conocimiento, manejo y conservación by Vides-Almonacid, Roberto

Subjects: “…CONSERVACION DE RECURSOS NATURALES 25847…”

Las reservas celulares forestales: respuestas campesinas a problemas globales by Reyes Cruz, Heladio

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Proceedings of second Pan American scientific congress : conservation in its relation to industrial evolution / by Hess, Ralph Henry

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Proceedings of second Pan American scientific congress : the people's interest in water-power resources / by Smith, George Otis

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Proceedings of second Pan American scientific congress : irrigation in the United States / by Fortier, Samuel

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Proceedings of second Pan American scientific congress : the conservation of copper / by Emmons, W. H.

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Proceedings of second Pan American scientific congress : conservation of metals by the recovery and use of scrap metals and drosses / by Dunlop, John P.

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Proceedings of second Pan American scientific congress : engineering work of the United States reclamation service / by Davis, Arthur Powell

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Proceedings of second Pan American scientific congress : the function of live stock in agriculture / by Rommel, George M.

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Proceedings of second Pan American scientific congress : great central markets for live stock and meats / by Hall, Louis D.

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Proceedings of second Pan American scientific congress : the advisability of collegiate courses on marketing and distribution / by Carver, T. N.

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Proceedings of second Pan American scientific congress : opportunities afforded the railroads of the United States for profitable agricultural development work / by Powell, T. F.

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Proceedings of second Pan American scientific congress : securing settlers for private irrigation projects / by Shedd, H. G.

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Proceedings of second Pan American scientific congress : the valuation of water powers / by Hagenah, William J.

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Proceedings of second Pan American scientific congress : the institute of tropical agriculture of the Pacific coast / by Webber, Herbert J.

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Proceedings of second Pan American scientific congress : the development of a market news service / by Sherman, Wells A.

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