Sturgis & Davis 2013, p. 112. Sturgis, Russell; Davis, Francis A. (2013). "Round Arch". Sturgis' Illustrated Dictionary of Architecture and Building: An Unabridged Reprint of the 1901-2 Edition. Dover Architecture. Dover Publications. ISBN978-0-486-14840-3. Retrieved 2023-12-15.
Sturgis & Davis 2013, p. 115. Sturgis, Russell; Davis, Francis A. (2013). "Round Arch". Sturgis' Illustrated Dictionary of Architecture and Building: An Unabridged Reprint of the 1901-2 Edition. Dover Architecture. Dover Publications. ISBN978-0-486-14840-3. Retrieved 2023-12-15.