O. Kochukov, A. Mutule, Z. Krishans, and I. Oleinikova, “Model for Technical-Economic Analysis of ENTSO-E and IPS/UPS Power System Optimal Interconnection Concepts”, ECCE, vol. 28, no. 1, pp. 15–18, Jan. 2011, doi: 10.2478/v10144-011-0002-1.