Dongsoo Han Minkyu Lee Laeyoung Chang Hyunil Yang Open radio map based indoor navigation system. 844-846 2010 PerCom Workshops https://doi.org/10.1109/PERCOMW.2010.5470558 https://doi.ieeecomputersociety.org/10.1109/PERCOMW.2010.5470558 conf/percom/2010w db/conf/percom/percomw2010.html#HanLCY10