Bertolini, A., N. Beverini, A. De Michele, F. Fidecaro, and F. Mango. “A Sapphire Monolithic Differential Accelerometer As Core Sensor for Gravity Gradiometric Geophysical Instrumentation”. Annals of Geophysics, vol. 49, no. 4-5, Dec. 2006, doi:10.4401/ag-3111.