Perhaps you should try some spelling variations:
london mathematical » non mathematical, common mathematical, motion mathematical
theory studying » theory study, theory studies, theory string
theory studien » theory studies, theory studie, theorien studien

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: london mathematical ((theory studying) OR (theory studien)) texts.
• Adding a wildcard symbol may retrieve word variants: london mathematical ((theory studying) or (theory studien)) texts*.