The following license files are associated with this item:

Attribution-NonCommercial-NoDerivs 3.0 United States
This is an open access article, originally published at https://doi.org/10.1515/sjph-2017-0028
Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivs 3.0 United States This is an open access article, originally published at https://doi.org/10.1515/sjph-2017-0028