1. Godowski, R. (1981). Varieties of orthomodular lattices with a strongly full set of states. Demonstratio Mathematica XIV, 725–732.
2. Godowski, R. (1982). States on orthomodular lattices. Demonstratio Mathematica XV, 817–822.
3. Godowski, R. and Greechie, R. J. (1984). Some equations related to states on orthomodular lattices. Demonstratio Mathematica XVII, 241–250.
4. Greechie, R. J. (1971). Orthomodular lattices admitting no states. Journal of Combinatorial Theory 10, 119–132.
5. Gross, H. and Künzi, U. M. (1985). On a class of orthomodular quadratic spaces. L’enseignement mathématique 31, 187–212.