I have a 34 string Concert Zither made by "Fr. Voltava, Praha-Zizkov". This is stamped onto the top of the fretboard. The label inside was missing. "Fr. Voltava, Praha-Zizkov" is also stamped on all the ribs internally. I've dated it to circa 1914-1917 by the fact that it came with a battered copy of "Theoretisch-praktische Zitherschule von Friedrich Gutmann, neue Ausgabe von Georg Keller" (Edition Peters, Leipzig), which is the "Kriegsausgabe" wartime economy edition, and the handwriting in the book is the same as that on the carrying case, hence the date!

I have restored it.

Does anyone know anything about this maker?

Frantisek VOTAVA, not "Voltava" as I originally wrote.