A Modal Logic for Pawlak's Approximation Spaces with Rough Cardinality n. - Philippe Balbiani; Petar Iliev; Dimiter Vakarelov (Fundam. Informaticae, 2008)

Succinctness of Epistemic Languages. - Tim French 002; Wiebe van der Hoek; Petar Iliev; Barteld P. Kooi (IJCAI, 2011)

Knowledge and Action in Semi-public Environments. - Wiebe van der Hoek; Petar Iliev; Michael J. Wooldridge (LORI, 2011)

A logic of revelation and concealment. - Wiebe van der Hoek; Petar Iliev; Michael J. Wooldridge (AAMAS, 2012)

On the Relative Succinctness of Two Extensions by Definitions of Multimodal Logic. - Wiebe van der Hoek; Petar Iliev; Barteld P. Kooi (CiE, 2012)

On the succinctness of some modal logics. - Tim French 002; Wiebe van der Hoek; Petar Iliev; Barteld P. Kooi (Artif. Intell., 2013)

On the relative succinctness of some modal logics. - Petar Iliev (2013)

Some Exponential Lower Bounds on Formula-size in Modal Logic. - Hans van Ditmarsch; Jie Fan 001; Wiebe van der Hoek; Petar Iliev (Advances in Modal Logic, 2014)

On the relative succinctness of modal logics with union, intersection and quantification. - Wiebe van der Hoek; Petar Iliev (AAMAS, 2014)

The succinctness of the cover modality. - Hans van Ditmarsch; Petar Iliev (J. Appl. Non Class. Logics, 2015)

Frame-Validity Games and Absolute Minimality of Modal Axioms. - Philippe Balbiani; David Fernández-Duque; Andreas Herzig; Petar Iliev (Advances in Modal Logic, 2018)

Succinctness in Subsystems of the Spatial μ-Calculus. - David Fernández-Duque; Petar Iliev (FLAP, 2018)

Frame-validity Games and Lower Bounds on the Complexity of Modal Axioms. - Philippe Balbiani; David Fernández-Duque; Andreas Herzig; Petar Iliev (Log. J. IGPL, 2022)

On semantically labelled syntax trees and the non-existence of certain Sahlqvist formulae. - Petar Iliev (Log. J. IGPL, 2023)

On the number of different variables required to define the n-density or the bounded n-width of Kripke frames with some consequences for Sahlqvist formulae. - Petar Iliev (Log. J. IGPL, 2025)