Andreas Riener Markus Straub Alois Ferscha Time-Lag as Limiting Factor for Indoor Walking Navigation. 24-37 2009 EuroSSC http://dx.doi.org/10.1007/978-3-642-04471-7_3 conf/eurossc/2009 db/conf/eurossc/eurossc2009.html#RienerSF09