Донева, Б., М. Делипетров, Ѓ. Димов, and К. Блажев. “ГРАВИТАЦИСКО ПОЛЕ НА РЕПУБЛИКА МАКЕДОНИЈА”. Natural Resources and Technology, Vol. 11, no. 11, Dec. 2017, pp. 67-73, https://js.ugd.edu.mk/index.php/NRT/article/view/1994.