Speak with signs: Active learning platform for Greek Sign Language, English Sign Language, and their translationMaria Papatsimouli, Lazaros Lazaridis, Konstantinos-Filippos Kollias, Ioannis Skordas and George F. FragulisSHS Web Conf., 102 (2021) 01008DOI: https://doi.org/10.1051/shsconf/202110201008