Kelly Williams (May 11, 2003). “Background of the Guitar-Zither”. The Guitar-Zither Clearinghouse. 2021年2月3日閲覧。 terminology on the "Chorded zither" (referred Autoharp without trademark infringement with Oscar Schmidt International), "ギターツィター（英語版）" (patented by Fred Menzenhauer in 1894), and "Chord zither" (referred Guitar-Zither, appeared in The Oxford Companion（英語版） to Musical Instruments, and The New Grove Dictionaryen（英語版） of Musical Instruments).
minermusic.com
Gregg Miner and Kelly Williams (July 2011). “Selecting the Term”. Fretless Zithers. 2021年2月3日閲覧。 terminology and taxonomy of the "Fretless Zither" family instruments.
Kelly Williams (May 11, 2003). “Background of the Guitar-Zither”. The Guitar-Zither Clearinghouse. 2021年2月3日閲覧。 terminology on the "Chorded zither" (referred Autoharp without trademark infringement with Oscar Schmidt International), "ギターツィター（英語版）" (patented by Fred Menzenhauer in 1894), and "Chord zither" (referred Guitar-Zither, appeared in The Oxford Companion（英語版） to Musical Instruments, and The New Grove Dictionaryen（英語版） of Musical Instruments).
