Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petriiov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
petroov » petrov (Expand Search), petrioov (Expand Search), petruoov (Expand Search), petrooov (Expand Search)
petr » petri (Expand Search), petru (Expand Search), petro (Expand Search)
petroiu » petrioiu (Expand Search), petruoiu (Expand Search), petrooiu (Expand Search)
petroou » petrioou (Expand Search), petruoou (Expand Search), petrooou (Expand Search)
petroiou » petrioiou (Expand Search), petruoiou (Expand Search), petrooiou (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 ((petriov OR petroov) OR ((petr OR (petroiu OR (petroou OR petroiou))) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petroov) OR ((petr OR (petroiu OR (petroou OR petroiou))) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petroov) OR ((petr OR (petroiu OR (petroou OR petroiou))) OR peter)) o.s.*.