Katusekattematerjal: erinevus redaktsioonide vahel

# [http://www.cedarbureau.org/frequently-asked-questions/product/grading-and-manufacturing.asp "Grading and Manufacturing | Products | Cedar Shake and Shingle Bureau"][http://www.cedarbureau.org/frequently-asked-questions/product/grading-and-manufacturing.asp] ''www.cedarbureau.org''. RetrievedKasutatud 2015-10-28.

# The glory of copper; ''Metal Roofing Magazine,'' DecemberDetsember 2002/JanuaryJaanuar 2003

# [http://roofingroger.com/roofing-requirements-one-and-two-family-dwellings/ "Roofing Requirements One- and Two- Family Dwellings"] [http://roofingroger.com/roofing-requirements-one-and-two-family-dwellings/] Regulatory Services Department. RetrievedKasutatud 29. Augustaugust 2015. <q>Asphalt-based organic and fiberglass shingles may only be used on roofs with slopes of 2:12 and greater.</q>