Overhead power line (English Wikipedia)

"Chapter 6. Visual aids for denoting obstacles" (PDF). Annex 14 Volume I Aerodrome design and operations. International Civil Aviation Organization. 2004-11-25. Retrieved 1 June 2011. 6.2.8 ... spherical ... diameter of not less than 60 cm. ... 6.2.10 ... should be of one colour.

books.google.com

Kynge, James (8 June 2018). "China's global power play". Financial Times. Retrieved 10 June 2018.

Harnesk, Tommy (9 January 2015). "Helikoptermonterad motorsåg snabbkapar träden". Ny Teknik (in Swedish). Archived from the original on 2015-01-12. Retrieved 12 January 2015.

Weger, Travis (2017-11-14). "WAPA Helicopters: Saving Time and Money". TDWorld. Retrieved 2017-12-07.
Freimark, Bruce (October 1, 2006). "Six Wire Solution". Transmission & Distribution World. Retrieved March 6, 2007.

"Powering Up - Vertical Magazine - The Pulse of the Helicopter Industry". verticalmag.com. Archived from the original on 4 October 2015. Retrieved 4 October 2015.
Head, Elan (April 2015). "High-value cargo". Vertical Magazine. pp. 80–90. Archived from the original on 19 April 2015. Retrieved 11 April 2015.
Maher, Guy R. (April 2015). "A cut above". Vertical Magazine. pp. 92–98. Archived from the original on 12 May 2015. Retrieved 11 April 2015.

"Powering Up - Vertical Magazine - The Pulse of the Helicopter Industry". verticalmag.com. Archived from the original on 4 October 2015. Retrieved 4 October 2015.
"Advanced Rubber Products - Suspension Insulators". Archived from the original on 2022-03-18. Retrieved 2013-09-17.
Head, Elan (April 2015). "High-value cargo". Vertical Magazine. pp. 80–90. Archived from the original on 19 April 2015. Retrieved 11 April 2015.
Maher, Guy R. (April 2015). "A cut above". Vertical Magazine. pp. 92–98. Archived from the original on 12 May 2015. Retrieved 11 April 2015.
Harnesk, Tommy (9 January 2015). "Helikoptermonterad motorsåg snabbkapar träden". Ny Teknik (in Swedish). Archived from the original on 2015-01-12. Retrieved 12 January 2015.