Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), petruuov (Expand Search), petrouov (Expand Search), peruov (Expand Search)
petra » petru (Expand Search), petro (Expand Search), petre (Expand Search), petrua (Expand Search), petroa (Expand Search), pera (Expand Search)
petroi » petro (Expand Search), petrov (Expand Search), petrow (Expand Search), petruoi (Expand Search), petrooi (Expand Search), peroi (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (Expand Search)
petruuiiv » petruuuiiv (Expand Search), petrouuiiv (Expand Search), peruuiiv (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (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 (petra OR (((petri OR petroi) OR petruuiiv) OR peruuiv))) OR (petr OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruov OR (petra OR (((petri OR petroi) OR petruuiiv) OR peruuiv))) OR (petr OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruov OR (petra OR (((petri OR petroi) OR petruuiiv) OR peruuiv))) OR (petr OR peter)) o.s.*.