@unpublished{TUW-296798, author = {Retscher, G{\"u}nther}, title = {Covid-19 Contact Tracing Apps - Is Bluetooth a Reliable Technique for Distance Estimation?}, year = {2012}, note = {invited; talk: GIS Ostrava 2021 - Advances in Localization and Navigation, Ostrava, Czech Republic; 2012-01-23 -- 2012-01-25} }