https://www.ehstoday.com/construction/osha-cites-roofing-contractors-colorado-site
https://www.facilitiesnet.com/roofing/article/How-to-Select-Roofing-Systems---18484
https://economictimes.indiatimes.com/small-biz/productline/building-materials/roofing-sheets-their-types-applications-and-costs-in-india/articleshow/69924678.cms
https://www.premierroofingservice.com/siding/
