Practical Linguistic Steganography Using Contextual Synonym Substitution and Vertex Colour Coding Ching-Yun Chang author Stephen Clark author 2010-10 text Proceedings of the 2010 Conference on Empirical Methods in Natural Language Processing Hang Li editor Lluís Màrquez editor Association for Computational Linguistics Cambridge, MA conference publication chang-clark-2010-practical https://aclanthology.org/D10-1116/ 2010-10 1194 1203