Hanna , Värri, Kaikko Juha, Horttanainen Mika, и Linnanen Lassi. 2008. Записки Горного института 174 (январь), 113-15. https://pmi.spmi.ru/pmi/article/view/7499.

Hanna , Värri, Kaikko Juha, Horttanainen Mika, and Linnanen Lassi. 2008. “Reduction of Greenhouse Gas Emissions in the District Heating System of Vyborg”. Journal of Mining Institute 174 (January), 113-15. https://pmi.spmi.ru/pmi/article/view/7499.