Clicking on the above link will let you listen to the Swedish folksong “Kristallen den fina” played on zitheroos by a quartet from the Archipelago Singers (the song is on the Archipelago Singers CD Odyssé from 2003).
They play four-part harmony, the same parts normally sung in the traditional male chorus arrangement by O. F. Tullberg.
The zitheroo is used in other recordings, for example 3 songs on “Labbetruten”, a Norwegian CD from 2004 with songs by Alf Prøysen sung by the group Måltrosten. This CD was part of a “music in the schools” package provided to all schools in Norway by the government.