The so called Oppler's theory on synagogue's architecture was published for the first time in 1884 as a chapter Synagogen und jüdische Begräbnisplätze of the book Baukunde des Architekten . It was the first coherent theory on architecture and style of Jewish temples. After Oppler's death, his article was edited and published again by his co-worker Albrecht Haupt. Morover, Haupt added some comments  on the technical aspects - he put his additions in square brackets, so it's easy to divide them from the original text.