Perhaps you should try some spelling variations:
petriiv » petriiiv (Expand Search), petroiiv (Expand Search), periiv (Expand Search)
petruiv » petriuiv (Expand Search), petrouiv (Expand Search), peruiv (Expand Search), pentruiv (Expand Search), petriiv (Expand Search)
petr » petri (Expand Search), petro (Expand Search), per (Expand Search)
petru » petriu (Expand Search), petrou (Expand Search), peru (Expand Search), pentru (Expand Search), petri (Expand Search)
petroi » petrioi (Expand Search), petrooi (Expand Search), peroi (Expand Search), petri (Expand Search), petro (Expand Search), petrov (Expand Search)
petrovs » petriovs (Expand Search), petroovs (Expand Search), perovs (Expand Search), petrov (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 ((petriiv OR petruiv) OR ((((petr OR petru) OR petroi) OR (petrovs OR perio)) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriiv OR petruiv) OR ((((petr OR petru) OR petroi) OR (petrovs OR perio)) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriiv OR petruiv) OR ((((petr OR petru) OR petroi) OR (petrovs OR perio)) OR peter)) o.s.*.