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)
petriooiu » petriiooiu (Expand Search), petruiooiu (Expand Search), petroiooiu (Expand Search)
petrou » petriou (Expand Search), petruou (Expand Search), petroou (Expand Search), petru (Expand Search), petro (Expand Search), petrov (Expand Search)
petriou » petriiou (Expand Search), petruiou (Expand Search), petroiou (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 (petriooiu OR (petrou OR petriou))) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petroov) OR ((petr OR (petriooiu OR (petrou OR petriou))) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petroov) OR ((petr OR (petriooiu OR (petrou OR petriou))) OR peter)) o.s.*.