Kłopotek, Mieczysław, Sławomir Wierzchoń, Krzysztof Ciesielski, Michał Dramiński, Dariusz Czerski, and Mariusz Kujawiak. 2006. “Map Quality Measurements for GNG and SOM Based Document Collection Maps”. Studia Informatica. System and Information Technology 7 (1-2):65-76. https://czasopisma.uph.edu.pl/studiainformatica/article/view/2851.