Grouping Ceramic Variability with pXRF for Pottery Trade and Trends in Early Medieval Southern Tuscany. Preliminary Results from the Vetricella Case Study (Grosseto, Italy) oleh Cristina Fornacelli, Vanessa Volpi, Elisabetta Ponta, Luisa Russo, Arianna Briano, Alessandro Donati, Marco Giamello, Giovanna Bianchi