Widomski, Marcin K., Piotr Gleń, Grzegorz Łagód, and Katarzyna M. Jaromin-Gleń. 2015. “Sustainable Development of One of the Poorest Province of the European Union: Lublin Voivodeship, Poland – Attempt of Assessment”. Problemy Ekorozwoju 10 (2):137-49. https://ph.pollub.pl/index.php/preko/article/view/4917.