“Gradner G’sang” from Austria sing Dos olte Bauernhaus or That Old Farmhouse translated into English.

Here’s what they have to say about themselves.

“We have been around for 20 years as the “Gradner G’sang”. We also sing songs, now long forgotten, thereby keeping the old traditions alive.”

Here’s everyone at this web link, photos, names and info:

And here’s the link to Strasser Accordions who have been around even longer than “Gradner G’sang”.
That’s since 1926. The Strasser website in English is here