Rellotges atňmics per calcular el geoide amb més precisió <a href="http://www.technologyreview.com/view/429238/atomic-clocks-to-measure-earths-geoid-from-the/">http://www.technologyreview.com/view/429238/atomic-clocks-to-measure-earths-geoid-from-the/</a><br>
<br>Raf<br>