I am writing a paper and I have to include all the historical eras of Greece as a pre-defined "vocabulary" for a metadata schema. This vocabulary has to be online and be accessible via a URL.
So I am searching for a URL that contains all the historical eras of Greece in a format like "era name" - "date started" - "date ended".
I cannot find a valid source. I want the source to be official. I used lots of keywords, Googling but nothing worthy except wikipedia. Can you suggest anything more official and trustworthy?