1. CIGRE Technical Brochure 518. Outdoor insulation in polluted conditions: guidelines for selection and dimensioning. Part 2 the DC case. Working Group C4.303. Paris (2012). www.e-cigre.org
2. CIGRE Green Book. Overhead Lines. Springer, Paris. ISBN 978-2-85873-284-5 (2014). www.e-cigre.org
3. CIGRE Technical Brochure 583.Guide to the conversion of existing AC lines to DC operation. Working Group B2.41. Paris (2012). www.e-cigre.org
4. CIGRE Technical Brochure 388. Impacts of HVDC lines on the economics of HVDC projects. Joint Working Group B2/B4/C1.17. Paris (2009). www.e-cigre.org
5. CIGRE Technical Brochure 63. Guide to procedures for estimating the lightning performance of transmission lines. WG 33.01. Paris (1991). www.e-cigre.org