1. Kuo, S.-S., Agazzil, O.E.: Keyword spotting in poorly printed documents using pseudo 2-D hidden Markov models. In: IEEE, pp. 0162–8828 (1994)
2. The legacy tobacco document library (LTDL) at UCSF (2006). http://legacy.library.ucsf.edu/
3. Doermann, D., Rivlin, E., Weiss, I.: Logo recognition using geometric invariants. In: Proceedings of International Conference on Document Analysis and Recognition, pp. 897–7 (1993)
4. Doermann, D., Rivlin, E., Weiss, I.: Applying and differential invariants for logo recognition. Mach. Vis. Appl. 9(2), 73–86 (1996)
5. Neumann, J., Samet, H., Soffer A.: Integration and global shape analysis for logo classification. Pattern Recognit. Lett. 23(12), 1449–1457 (2002)