Perhaps you should try some spelling variations:
"formal languages and automatic theory" » "formal languages and automatic theorem", "formal languages and automation theory", "formal languages and axiomatic theory", "formal language and automatic theory"
"formal languages and automata theory" » "formal language and automata theory"
"formal languages and automated theorem" » "formal language and automated theorem"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("formal languages and automata theory") OR ("formal languages and automatic theory"))) OR ("formal languages and automated theorem"))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"formal languages and automata theory\") OR (\"formal languages and automatic theory\"))) or (\"formal languages and automated theorem\"))*".
• Removing quotes may allow a broader search: (((( formal languages and automata theory ) OR ( formal languages and automatic theory ))) or ( formal languages and automated theorem ))*.