Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), peteriov (Expand Search), petriiov (Expand Search), petroiov (Expand Search)
petroiv » petrov (Expand Search), petriv (Expand Search), petrovv (Expand Search), peteroiv (Expand Search), petrioiv (Expand Search), petrooiv (Expand Search)
petru » pentru (Expand Search), petri (Expand Search), peteru (Expand Search), petriu (Expand Search), petrou (Expand Search)
pero » petro (Expand Search), pro (Expand Search)
petroi » petri (Expand Search), petro (Expand Search), petrov (Expand Search), peteroi (Expand Search), petrioi (Expand Search), petrooi (Expand Search)
petriou » peteriou (Expand Search), petriiou (Expand Search), petroiou (Expand Search)
petr » peter (Expand Search), petri (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 ((petriov OR petroiv) OR ((((petru OR petriou) OR pero) OR petroi) OR (petr OR per))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petroiv) OR ((((petru OR petriou) OR pero) OR petroi) OR (petr OR per))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petroiv) OR ((((petru OR petriou) OR pero) OR petroi) OR (petr OR per))) o.s.*.