Tài liệu tham khảo WikiPedia: Bánh_vòng http://archives.cbc.ca/IDC-1-69-1371-8375/life_soc... http://www.boston.com/lifestyle/food/articles/2008... http://lambanh365.com/cach-lam/cach-lam-banh-donut... http://query.nytimes.com/gst/fullpage.html?res=940... https://archive.org/details/donutsamericanpa00edge https://commons.wikimedia.org/wiki/Doughnut?uselan... https://tuoitre.vn/chi-1-000-usd-mua-mot-chiec-ban...
