1. Lecture Notes in Computer Science;J.A. Alonso,2007
2. Barnes, T., Stamper, J.: Automatic Hint Generation for Logic Proof Tutoring Using Historical Data. Educational Technology & Society 13(1), 3–12 (2010)
3. Baronett, S.: Logic. Pearson (2008)
4. Lecture Notes in Computer Science;C.-G. Chiru,2012
5. Lecture Notes in Computer Science;J.C. Gluz,2012