ANANYA DASS, CEM AKSOY, AGGELIKI DIMITRIOU, and DIMITRI THEODORATOS. “RELAXATION OF KEYWORD PATTERN GRAPHS ON RDF DATA”. Journal of Web Engineering, vol. 16, no. 5-6, Mar. 2017, pp. 363-98, https://journals.riverpublishers.com/index.php/JWE/article/view/3267.