@article {185, title = {Relative Positioning System Using Acoustic Sensors for Ubiquitous Computing Applications}, journal = {UPGRADE, The European Journal for the Informatics Professional}, volume = {6}, year = {2005}, month = {00/2005}, pages = {39-45}, publisher = {Nov{\'a}tica}, address = {Espa{\~n}a}, issn = {1684-5285}, author = {Carlos De Marzziani and Ure{\~n}a, J. and {\'A}lvaro Hern{\'a}ndez and Manuel Mazo and Ana Jimenez and Fernando J. {\'A}lvarez and Jos{\'e} Manuel Villadangos} }