Perhaps you should try some spelling variations:
petrw » petrow (Expand Search), petri (Expand Search), petro (Expand Search), peterw (Expand Search), petriw (Expand Search)
petru » pentru (Expand Search), petri (Expand Search), peteru (Expand Search), petriu (Expand Search), petrou (Expand Search)
petruov » pentruov (Expand Search), petriov (Expand Search), peteruov (Expand Search), petriuov (Expand Search), petrouov (Expand Search), petrov (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petro (Expand Search)
petroi » peteroi (Expand Search), petrioi (Expand Search), petrooi (Expand Search), petri (Expand Search), petro (Expand Search), petrov (Expand Search)

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: fop ((((petrw OR petru) OR petrw) o) OR ((petr OR (petroi OR (petroi OR petruov))) _)). s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petrw OR petru) OR petrw) o) OR ((petr OR (petroi OR (petroi OR petruov))) _)). s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petrw OR petru) OR petrw) o) OR ((petr OR (petroi OR (petroi OR petruov))) _)). s.*.