Synthesis of yellow and red ochre: a preliminary multi-analytical, micro-invasive investigation on recipes and recognition criteriaMichela Botticelli, Gaia Appolloni, António Candeias, José Mirão and Adriana MarasEur. Phys. J. Plus, 136 3 (2021) 322DOI: https://doi.org/10.1140/epjp/s13360-021-01291-5