Variable Grammars: Verbal Agreement in Northern Dialects of English

"Pietsch has not only provided a milestone in his genuinely original contribution to the scholarly Fachliteratur; he is also exemplary in the thoroughness with which he has conducted his research at every level and also in the easefulness with which he has conceived and presented it. Difficult, complex ideas are conveyed with commendable cogency and clarity. Innovation in cartographic design provides effective interpretations. Pietsch shorws that he is as much at home with reading his data, marshalling frequencies into analysed data subsets, and conducting statistical tests, as he is with dealing with linguistic history and evolution, interpreting variation and change and engaging trenchantly with theory. This is, without doubt, a mouldbreaking study of its subject and a model for others to follow."
John M. Kirk in: Zeitschrift für Dialektologie und Linguistik Heft 2 (2010)