Clackamas Community College, IUPAC Names, arhivat din original la , accesat în
doi.org
Maybery, C.F. (). „On the Composition of the Ohio and Canadian Sulphur Petroleums”. Proceedings of the American Academy of Arts and Sciences. 31: 1–66. doi:10.2307/20020618. JSTOR20020618.
„butter (n)”, Online Etymology Dictionary, accesat în
jstor.org
Maybery, C.F. (). „On the Composition of the Ohio and Canadian Sulphur Petroleums”. Proceedings of the American Academy of Arts and Sciences. 31: 1–66. doi:10.2307/20020618. JSTOR20020618.