Demetriou IC, Lipitakis EA. Measuring the smoothing performance of least squares approximation by non-negative divided differences. HERMIS - $\mu\pi$ Intl. Journal. 2001;Vol. 2:115-131.

Demetriou IC, Lipitakis EA. Certain positive definite submatrices that arise from binomial coefficient matrices. Applied Numerical Mathematics. 2001;36:219-229.

Demetriou IC. Calculating the production and distribution cost curve by using third divided differences and least squares approximation. In: The International Soc. of Logistics, Proceedings of the 17th International Logistics Congress. ; 2001. pp. 19-28.

Demetriou IC. The methodology of the IMSL / LCONF subroutine for nonlinear programming in some difficult problems (Η μεθοδολογία της ρουτίνας IMSL / LCONF για γραμμικά περιορισμένη βελτιστοποίηση σε κάποια δύσκολα προβλήματα). In: Proceedings of the 14th Hellenic Conference on Statistics, Skiathos, Greek Statistical Institute. ; 2001. pp. 127-134.

Demetriou IC. Computational experience with a Fortran package for least squares convex-concave data smoothing. In: Proceedings of the 5th Conference on Informatics and Mathematics, HERCMA 2001, Athens, Greece. EA Lipitakis, Editor. ; 2001. pp. 487-493.