1. Modeling of surface dust concentrations using neural networks and kriging
2. London Metal Exchange, available at http://www.lme.com.
3. Metall-Expert, available at http://metalexpert.com/ru/index.html.
4. Steel Statistical Yearbook 2012 (World Steel Association, Brussels, Belgium, 2012).
5. The Central Bank of Russian Federation, available at http://cbr.ru/currency_base.