Soussi, Nassima, and Mohamed Bahaj. “Semantics Preserving SQL-to-SPARQL Query Translation for Nested Right and Left Outer Join”. Journal of Applied Research and Technology 15, no. 5 (June 14, 2019). Accessed April 28, 2024. https://jart.icat.unam.mx/index.php/jart/article/view/694.