Perhaps you should try some spelling variations:
petroov » petrov (Expand Search), petrioov (Expand Search), petrooov (Expand Search), peroov (Expand Search)
petroiv » petrov (Expand Search), petrioiv (Expand Search), petrooiv (Expand Search), peroiv (Expand Search)
petru » pentru (Expand Search), petri (Expand Search), petriu (Expand Search), petrou (Expand Search), peru (Expand Search)
petruo » pentruo (Expand Search), petrio (Expand Search), petriuo (Expand Search), petrouo (Expand Search), peruo (Expand Search), petro (Expand Search)
petr » petri (Expand Search), petro (Expand Search), per (Expand Search)
petriio » petriiio (Expand Search), petroiio (Expand Search), periio (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 ((petroov OR petroiv) OR (((petru OR petr) OR ((petruo OR petriio) OR peteruo)) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petroov OR petroiv) OR (((petru OR petr) OR ((petruo OR petriio) OR peteruo)) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petroov OR petroiv) OR (((petru OR petr) OR ((petruo OR petriio) OR peteruo)) OR peter)) o.s.*.