BUKU BAGUS
https://books.google.co.jp/books?id=ZblDDwAAQBAJ&lpg=PA528&ots=VRa0eEKiik&dq=positioning%20and%20navigation%20in%20complex%20environments%20downloAD%20pdf&pg=PR8#v=onepage&q&f=false
the note and web link about education for sharing knowledge