Noboru Abe and  Yoshinori Amai and  Toshinori Nakatake and  Sumio Masuda and  Kazuaki Yamaguchi,  An Algorithm for the Map Labeling Problem with Two Kinds of Priorities.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    April 2014, vol. 89(5). 802 - 805
    [viewed 26 October 2021]. Available from: