↑Ringe, Donald; Taylor, Ann (2014) The Development of Old English (A Linguistic History of English; 2), 牛津: 牛津大学出版社, ISBN978 0 19 920784 8, 页308: “PWGmc *ferh ‘life’, gen. sg. *ferhas”
↑Ringe, Donald; Taylor, Ann (2014) The Development of Old English (A Linguistic History of English; 2), 牛津: 牛津大学出版社, ISBN978 0 19 920784 8, 页313: “PWGmc *ferh(u?)”