L. B. Khanh, H. Nguyen Thi Thu, and T. Dao Thanh, “Deep Level Markov Chain Model for Semantic Document Retrieval”, EAI Endorsed Scal Inf Syst, vol. 5, no. 19, p. e1, Sep. 2018, doi: 10.4108/eai.19-6-2018.155443.