@misc {IOPORT.70525994,
    author       = {Sunaga, Hikaru and Hada, Takashi and Akiyama, Masaki and Ioroi, Shigenori and Tanaka, Hiroshi},
    title        = {Discrimination of multiple objects and expanding positioning area for indoor positioning systems using ultrasonic sensors},
    howpublished = {AmI, 31-40 (2011).},
    year         = {2011},
    doi          = {10.1007/978-3-642-25167-2_4},
    identifier   = {70525994},
}