1980, Frederick B. Agard,The Genealogy of the French Language, published inContributions to historical linguistics,→ISBN, page222:
These, together with (some) Romanshlects, belong to our West Rhaetian; the /ȫ/ also supported by twolects from the Ticino which by our criteria are NWIt, and by the partially umlautinglects of Lombardy which together with (some) Engadinelects belong to our East Rhaetian.