P. Popivanov, I. Iordanov, Anomalous singularities of the solutions to several classes of weakly hyperbolic systems. Examples, Progress in Analysis, Proc. of 3rd ISAAC congress, 2001, Berlin, Editors: G.W. Begehr, R.P. Gilbert, M.W. Wong, Singapore 2003, vol. 1, 697-703.

P.Popivanov, I. Iordanov, On the Anomalous Singularities of the Solutions to Some Classes of Weakly Hyperbolic Semilinear Systems. Systems. Banach Center Publ. volume 60, Warszawa 2003, 209-218.

I. Iordanov, P.Popivanov, Weakly Hyperbolic Systems Having Infinite Order of Tangency Between Two Characteristics - Regularizing Effect on the Anomalous Singularities, Comptes rendus de l'Acad. bul. Sci., t. 56, No 12, 2003, 11-16.

Iordanov, Iordan V., Stoyan V. Stoyanov, and Andrey A. Vassilev, Price dynamics in a two region model with strategic interaction, Proceedings of the Spring Conference of the Union of Bulgarian Mathematicians, 2004, 144-149.

Vassilev, Andrey A., Iordan V. Iordanov and Stoyan V. Stoyanov, A strategic model of trade between two regions with continuos-time price dynamics, Comptes rendus de l'Acad bul. Sci., t. 58, No 4, 2005, 361-366.

Й. Йорданов, Т. Черногорова, В. Ракидзи, Математика за студенти по икономика и управление, Университетско издателство "Св. Кл. Охридски", 2005, София.

Iordanov, Iordan V. and Andrey A. Vassilev, Optimal relocation strategies for spatially mobile consumers, 2006, work in progress.