“…Analysis of the six individual calibrations compared with their mean showed a maximum-to-minimum variation of 25% in the gradient term and 14% in the intercept term, with no systematic trend between data sets. Calibrations of the resonator were performed with a set of standard samples detailed in [21], [26], [27]. All were characterized in a split post resonator [21], [26], except the quartz and LaAlO3 for which standard values were assumed [27].…”