Esche, P. G., Fiedler, H., & Uttikal, D. (1975). Carl Zeiss Jena: Fortschritt Technik Tradition. Carl Zeiss Jena.
Lua i Stíl Chicago (17ú heag.)Esche, Paul Gerhard, Horst Fiedler, agus Detlef Uttikal. Carl Zeiss Jena: Fortschritt Technik Tradition. Jena: Carl Zeiss Jena, 1975.
Lua MLA (8ú heag.)Esche, Paul Gerhard, et al. Carl Zeiss Jena: Fortschritt Technik Tradition. Carl Zeiss Jena, 1975.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.