Calculating pressure with elastic geobarometry: A comparison of different elastic solutions with application to a calc-silicate gneiss from the Rhodope Metamorphic Province - Moulas, Evangelos; Kostopoulos, Dimitrios; Podladchikov, Yury; Chatzitheodoridis, Elias; Schenker, Filippo; Zingerman, Konstantin; Pomonis, Panagiotis; Tajčmanová, Lucie (Lithos, 2020)