Alistair Campbell (1959), Old English Grammar

Diarmaid Ó Muirithe (1978), The Anglo-Norman and their English Dialect of South-East Wexford

Joseph P. Crowley (1986), The study of old English dialects

J. Leclerc (2004), L'évolution de la langue anglaise

Joanna Bugaj (2004), Middle Scots Inflectional System in the South-west of Scotland

Raymond Hickey (2005), Dublin English: Evolution and Change

Jeremy Smith (2007), Sound Change and the History of English

Wayne Harbert (2007),The Germanic Languages

Arjen P. Versloot (2008), Mechanisms of Language Change: Vowel Reduction in 15th century West Frisian

Rolf Hendrik Bremmer (2009), An Introduction to Old Frisian

Jarich Hoekstra, Willem Visser, Goffe Jensma (2010), Studies in West Frisian Grammar

Michiel de Vaan (2011), West-Germanic *ai in Frisian

Richard M. Hogg (2011), A Grammar of Old English, Volume 1: Phonology

Patrick V. Stiles (2013), The Pan-West Germanic Isoglosses and the Subrelationships of West Germanic to Other Branches

Arjen P. Versloot (2014), The Runic Frisian vowel system: the earliest history of Frisian and Proto-Insular North Frisian

Frederik Kortlandt (2017), Old English and Old Frisian

Michiel de Vaan (2018), Historical Development of Dutch

Arjen P. Versloot (2019), Reduction of unstressed vowels in Proto-Frisian and the Germanic 'Auslautgesetze'

이재욱 (2020), (SET 총18권) 영국영어 사투리 전권 세트: 한국인을 위한 전세계 100가지 영어 사투리 영국 잉글랜드 영어기초+정통영어+북부영어+중부영어+동부영어+남부영어+런던영어 ALL SET

Livia Kaiser (2021), Runes Across the North Sea from the Migration Period and Beyond, An Annotated Edition of the Old Frisian Runic Corpus

Bernard Mees (2022), The English Language Before England, An Epigraphic Account

Glottolog (2022), Anglo-Frisian

Scotland's Census - Languages (2001-2011)

Ethnologue :

• Belgium, Luxembourg and Netherlands
• Celtic
• English (group)
• Frisian
• Ireland and United Kingdom