From Wikimedia Commons, the free media repository
- Gregg Miner. Organology: "Harp" forms of Related Stringed Instruments. www.harpguitars.net. ""True" Harp forms: / Mandolins / Ukuleles / Miscellaneous”, “"Pseudo" Harp forms: / Mandolins, Hollow-arm, lyre form / Mandolins, Hollow-arm, harp form / Ukuleles, Hollow-arm, harp form / Sympathetic Strings"
- mandolins - lyre mandolin or harp mandolin. ATLAS of Plucked Instruments. "Some mandolins got an unusually body-shape, like those based on instruments made by the Larson Brothers in the USA during the early 1900. The extra arm was probably meant to get some more volume.”, “Unlike the harp guitars, which had always some extra bass strings on the arm extention, most versions of the harp mandolin had no extra strings (like this modern version made by Musikalia). Only a few were actually made with 4 bass strings."