3. Results
In this section we provide an overview of the literature in terms of coverage by journals, over time, and categorization.
3.1. Sustainable locations
As mentioned previously, there are few studies with an explicit focus on issues concerning sustainable location. In an early study by Eagan and Joeres (1997), they present an assessment tool for evaluating the sustainability at a company level, which can be applied to facility location problems. One important breakthrough, as the authors claimed, is due to its attempt to transfer the fuzzy concept of sustainability by adopting and quantifying the 16 principles for sustainable development defined by International Chamber of Commerce. Nevertheless such principles are still mainly considering the environmental aspect of sustainability.