Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), peteruov (Expand Search), petruuov (Expand Search), petrouov (Expand Search)
petriiv » peteriiv (Expand Search), petruiiv (Expand Search), petroiiv (Expand Search)
petriiiv » peteriiiv (Expand Search), petruiiiv (Expand Search), petroiiiv (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petroou » peteroou (Expand Search), petruoou (Expand Search), petrooou (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (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 peteriv) OR (petriiv OR petriiiv)) OR ((petr OR petroou) OR petri)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petruov OR peteriv) OR (petriiv OR petriiiv)) OR ((petr OR petroou) OR petri)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petruov OR peteriv) OR (petriiv OR petriiiv)) OR ((petr OR petroou) OR petri)) o.s.*.