1. Abel, D. L., & Trevors, J. T. (2006). More than a metaphor: Genomes are objective sign systems. Journal of BioSemiotics, 1(2), 253–267.
2. Abler, R., Adams, J. S., & Gould, P. (1971). Spatial organisation. The geographer’s view of the world. Englewood Cliffs: Prentice-Hall.
3. AGIT. (2013). Creating the GISociety. AGIT 25 – Symposium und Fachmesse für Angewandte Geoinformatik.
http://www.agit.at/index.php/ueberuns/archiv/94-ueberuns-agit/archiv/161-archiv2013
4. Agnew, J., Livingstone, D. N., & Rogers, A. (1996). Human geography: An essential anthology. Oxford/Cambridge, MA: Blackwell.
5. Ahamer, G. (1997a, December). Supply and demand in energy and agriculture: Emitters of CO2 and possibilities for global biomass energy strategies. World Resource Review (WRR), 9(4), 491–507. ISSN 1042-8011. See
http://www2.msstate.edu/~krreddy/glowar/archive/wrrvol997.html