"Archived copy"(PDF). www.corning.com. Archived from the original(PDF) on 13 April 2015. Retrieved 15 January 2022.{{cite web}}: CS1 maint: archived copy as title (link)
"Archived copy"(PDF). www.corning.com. Archived from the original(PDF) on 13 April 2015. Retrieved 15 January 2022.{{cite web}}: CS1 maint: archived copy as title (link)