George Gargov Knowledge and Uncertainty and Ignorance in Logic: Bilattices and beyond. [Citation Graph (0, 0)][DBLP] Journal of Applied Non-Classical Logics, 1999, v:9, n:2-3, pp:- [Journal]
George Gargov An Approach to Uncertainty via Sets of Truth Values. [Citation Graph (0, 0)][DBLP] Notre Dame Journal of Formal Logic, 1995, v:36, n:2, pp:235-268 [Journal]