Perhaps you should try some spelling variations:
petroi » petro (Expand Search), petrov (Expand Search), petrow (Expand Search), peteroi (Expand Search), petrooi (Expand Search)
peteri » peterdi (Expand Search), peter (Expand Search), peters (Expand Search)
petruuv » pentruuv (Expand Search), peteruuv (Expand Search), petrouuv (Expand Search)
petru » pentru (Expand Search), peteru (Expand Search), petrou (Expand Search)
petri » peteri (Expand Search), petroi (Expand Search)
petris » peteris (Expand Search), petrois (Expand Search)
petr » peter (Expand Search), petro (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 ((petri OR petruuv) OR ((((petroi OR peteri) OR petru) OR petris) OR (petr OR per))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petri OR petruuv) OR ((((petroi OR peteri) OR petru) OR petris) OR (petr OR per))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petri OR petruuv) OR ((((petroi OR peteri) OR petru) OR petris) OR (petr OR per))) o.s.*.