ESAKIA, Leo and GRIGOLIA, Revaz. Formulas of one propositional variable in intuitionistic logic with the Solovay modality. Logic and Logical Philosophy. Online. 19 June 2008. Vol. 17, no. 1-2, pp. 111-127. [Accessed 19 December 2025]. DOI 10.12775/LLP.2008.007.