[1] |
Chellas, B. F.: Modal logic: an introduction. (1980) · Zbl 0431.03009 |

[2] |
Cohn, P. M.: Universal algebra. (1965) · Zbl 0141.01002 |

[3] |
Koczy, L. T.: Review of ”on a concept of rough sets” by zakowski. Mathematical review 84i, 03092 (1984) |

[4] |
Lin, T. Y.: Neighborhood systems and relational database. Proceedings of CSC’88 (1988) |

[5] |
Lin, T. Y.: Neighborhood systems and approximation in database and knowledge base systems. Proceedings of the fourth international symposium on methodologies of intelligent systems, poster session (1989) |

[6] |
Lin, T. Y.: Topological and fuzzy rough sets. Intelligent decision support: handbook of applications and advances of the rough sets theory, 287-304 (1992) |

[7] |
Lin, T. Y.: Neighborhood systems -- application to qualitative fuzzy and rough sets. Advances in machine intelligence and soft-computing, 132-155 (1997) |

[8] |
Lin, T. Y.; Liu, Q.: Rough approximate operators: axiomatic rough set theory. Rough sets, fuzzy sets and knowledge discovery, 256-260 (1994) · Zbl 0818.03028 |

[9] |
Lin, T. Y.; Liu, Q.; Huang, K. J.; Chen, W.: Rough sets, neighborhood systems and approximation. Proceedings of the fifth international symposium on methodologies of intelligent systems, 130-141 (25--27 October 1990) |

[10] |
Lin, T. Y.; Yao, Y. Y.: Mining soft rules using rough sets and neighborhoods. Proceedings of the symposium on modelling, analysis and simulation, computational engineering in systems applications (CESA’96), IMASCS multiconference, 1095-1100 (9--12 July 1996) |

[11] |
Orlowska, E.: Semantics of nondeterministic possible worlds. Bulletin of the Polish Academy of sciences: mathematics 33, 453-458 (1985) |

[12] |
Orlowska, E.: Semantics analysis of inductive reasoning. Theoretical computer science 43, 81-89 (1986) |

[13] |
Orlowska, E.: Kripke semantics for knowledge representation logics. Studia logica 49, 255-272 (1990) · Zbl 0726.03023 |

[14] |
Pawlak, Z.: Rough sets. International journal of computer and information science 11, 341-356 (1982) · Zbl 0501.68053 |

[15] |
Pawlak, Z.: Rough classification. International journal of man-machine studies 20, 469-483 (1984) · Zbl 0541.68077 |

[16] |
Pawlak, Z.: Rough sets: A new approach to vagueness. Fuzzy logic for the management of uncertainty, 105-118 (1992) |

[17] |
Pawlak, Z.: Hard and soft sets. Rough sets, fuzzy sets and knowledge discovery, 130-135 (1994) · Zbl 0819.04008 |

[18] |
Pomykala, J. A.: Approximation operations in approximation space. Bulletin of the Polish Academy of sciences: mathematics 35, 653-662 (1987) |

[19] |
Pomykala, J. A.: On definability in the nondeterministic information system. Bulletin of the Polish Academy of sciences: mathematics 36, 193-210 (1988) |

[20] |
Sierpenski, W.; Krieger, C.: General topology. (1956) |

[21] |
Slowinski, R.; Vanderpooten, D.: Similarity relation as a basis for rough approximations. Advances in machine intelligence and soft-computing, 17-33 (1997) |

[22] |
Wasilewska, A.: Conditional knowledge representation systems -- model for an implementation. Bulletin of the Polish Academy of sciences: mathematics 37, 63-69 (1987) |

[23] |
Wong, S. K. M.; Yao, Y. Y.: Roughness theory. Proceedings of the sixth international conference on information processing and management of uncertainty in knowledge-based systems, 877-883 (1--5 July 1996) |

[24] |
Wybraniec-Skardowska, U.: On a generalization of approximation space. Bulletin of the Polish Academy of sciences: mathematics 37, 51-61 (1989) · Zbl 0755.04011 |

[25] |
Yao, Y. Y.: Two views of the theory of rough sets in finite universes. International journal of approximate reasoning 15, 291-317 (1996) · Zbl 0935.03063 |

[26] |
Yao, Y. Y.; Lin, T. Y.: Generalization of rough sets using modal logic. Intelligent automation and soft computing, an international journal 2, 103-120 (1996) |

[27] |
Zakowski, W.: Approximations in the space $(U, {\pi})$. Demonstratio Mathematica 16, 761-769 (1983) · Zbl 0553.04002 |