@unpublished{TUW-283452, author = {Retscher, G{\"u}nther}, title = {Wi-Fi Positioning in Challenging Urban, Transitional and Indoor Environments}, year = {2019}, note = {invited; talk: Guest Lecture at the Institute of Geodesy of the University of Warmia and Mazury, Olsztyn, Polen; 2019-11-15} }