1. Interval Methods for Systems of Equations, Encyclopedia of Mathematics and its Applications (Cambridge University Press, 1990).
2. in: Mathematics and Education in Mathematics, Proceedings of the 33rd Spring Conference of the UBM (UBM, Sofia, 2004) pp. 446-451, (http://www.math.bas.bg/?epopova/papers/04smbEP.pdf).
3. Parametric Fixed-Point Iteration Implemented in C-XSC, Preprint BUW-WRSWT 2003/3, University of Wuppertal (2003). (http://www.math.uni-wuppertl.de/wrswt/preprints/prep_03_3.pdf)
4. in: Topics in Validated Computations, edited by J. Herzberger (Elsevier Science B. V, 1994), pp. 63-135.