See also:
https://forum.vintageairgunsgallery.com/homemade-non-production-airguns/homemade-girandoni-type-repeater/#post-6411
https://forum.vintageairgunsgallery.com/unknown-unmarked-airguns/homemade-air-rifle-reportedly-for-ww2-partisans/
https://forum.vintageairgunsgallery.com/air-pistols-all-types/girandoni-style-pistol-david-swan-collection/#post-901
https://forum.vintageairgunsgallery.com/air-pistols-all-types/staudenmayer-pistol/#post-896
https://forum.vintageairgunsgallery.com/air-pistols-all-types/auctioned-pistols-hermann-historica/
https://forum.vintageairgunsgallery.com/air-pistols-all-types/girandoni-type-repeater-pistol-attrib-eckert-eckard/#post-6422