Biblioteca del Congreso (Estados Unidos), 15 junio 2018 : catálogo electrónico https://goo.gl/RprwwD

His Dictionary of economic terms, 1966.

Dictionary of environmental law, 2000: CIP datasheet (Gilpin, Alan ; b. August 20, 1924)

Dictionary of environment and sustainable development, 1996: portada (Alan Gilpin)