Minh Bao, T., T. Cong Tuan, and H. Trong Duc. “Querying Object-Oriented Databases Based on Signature Graph and N-Ary Tree”. EAI Endorsed Transactions on Context-Aware Systems and Applications, vol. 3, no. 7, Feb. 2016, p. e4, doi:10.4108/eai.12-2-2016.151087.