Perhaps you should try some spelling variations:
perov » petrov (Expand Search)
petro » petrov (Expand Search), petri (Expand Search), petru (Expand Search), petero (Expand Search), petrio (Expand Search), petruo (Expand Search)
petruiv » peteruiv (Expand Search), petriuiv (Expand Search), petruuiv (Expand Search)
petriio » peteriio (Expand Search), petriiio (Expand Search), petruiio (Expand Search)
petriu » peteriu (Expand Search), petriiu (Expand Search), petruiu (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petru (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 ((petruiv OR perov) OR ((((petro OR (petriio OR peterio)) OR peteru) OR petriu) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruiv OR perov) OR ((((petro OR (petriio OR peterio)) OR peteru) OR petriu) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruiv OR perov) OR ((((petro OR (petriio OR peterio)) OR peteru) OR petriu) OR petr)) o.s.*.