Alexander Bergs, Modern Scots, Languages of the World series, № 242 (Bow Historical Books, 2001), ISBN 978-3-89586-513-8, p. 4, 50. "Scots developed out of a mixture of Scandinavianised Northern English during the early Middle English period.... Scots originated as one form of Northern Old English and quickly developed into a language in its own right up to the seventeenth century."
Sandred, Karl Inge«Good or Bad Scots?: Attitudes to Optional Lexical and Grammatical Usages in Edinburgh».Acta Universitatis Upsaliensis.Ubsaliensis S. Academiae,48,1983,p.13.«Whereas Modern Standard English is traced back to an East Midland dialect of Middle English, Modern Scots developed from a northern variety which goes back to Old Northumbrian»
