"Archived copy"(PDF). www.nrel.gov. Archived from the original(PDF) on 4 March 2016. Retrieved 14 January 2022.{{cite web}}: CS1 maint: archived copy as title (link)
"Archived copy"(PDF). www.nrel.gov. Archived from the original(PDF) on 4 March 2016. Retrieved 14 January 2022.{{cite web}}: CS1 maint: archived copy as title (link)