Minkyu Lee Hyunil Yang Dongsoo Han Chansu Yu Crowdsourced radiomap for room-level place recognition in urban environment. 648-653 2010 PerCom Workshops https://doi.org/10.1109/PERCOMW.2010.5470515 https://doi.ieeecomputersociety.org/10.1109/PERCOMW.2010.5470515 conf/percom/2010w db/conf/percom/percomw2010.html#LeeYHY10