Ulrich Heink et Ingo Kowarik, « What are indicators? On the definition of indicators in ecology and environmental planning », Ecological Indicators, vol. 10, no 3, , p. 584–593 (ISSN1470-160X, DOI10.1016/j.ecolind.2009.09.009, lire en ligne, consulté le )
Ulrich Heink et Ingo Kowarik, « What are indicators? On the definition of indicators in ecology and environmental planning », Ecological Indicators, vol. 10, no 3, , p. 584–593 (ISSN1470-160X, DOI10.1016/j.ecolind.2009.09.009, lire en ligne, consulté le )
Ulrich Heink et Ingo Kowarik, « What are indicators? On the definition of indicators in ecology and environmental planning », Ecological Indicators, vol. 10, no 3, , p. 584–593 (ISSN1470-160X, DOI10.1016/j.ecolind.2009.09.009, lire en ligne, consulté le )