Navegació interior pel camp magnčtic <a href="http://www.popsci.com/technology/article/2012-07/video-mapping-earths-magnetic-field-app-allows-indoor-navigation">http://www.popsci.com/technology/article/2012-07/video-mapping-earths-magnetic-field-app-allows-indoor-navigation</a> #comElsAltresAnimals<br>
<br>Raf<br>