Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), petruuov (Expand Search), petrouov (Expand Search), peruov (Expand Search)
petrouo » petruouo (Expand Search), petroouo (Expand Search), perouo (Expand Search), petruo (Expand Search), petroo (Expand Search), petrovo (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (Expand Search)
petrou » petruou (Expand Search), petroou (Expand Search), perou (Expand Search), petru (Expand Search), petro (Expand Search), petrov (Expand Search)
petroou » petruoou (Expand Search), petrooou (Expand Search), peroou (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (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 (petruov OR ((petrouo OR petrouo) OR ((petr OR ((petrou OR petroou) OR petri)) OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petruov OR ((petrouo OR petrouo) OR ((petr OR ((petrou OR petroou) OR petri)) OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (petruov OR ((petrouo OR petrouo) OR ((petr OR ((petrou OR petroou) OR petri)) OR peter))) o.s.*.