Perhaps you should try some spelling variations:
perov » petrov (Expand Search)
petrouo » petrovuo (Expand Search), petriuo (Expand Search), petruuo (Expand Search), peterouo (Expand Search), petriouo (Expand Search), petruouo (Expand Search)
petro » petrov (Expand Search), petri (Expand Search), petru (Expand Search), petero (Expand Search), petrio (Expand Search), petruo (Expand Search)
petruov » peteruov (Expand Search), petriuov (Expand Search), petruuov (Expand Search)
petrui » peterui (Expand Search), petriui (Expand Search), petruui (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 ((perov OR (petruov OR periuov)) OR ((petrouo OR petrui) OR (petro OR petr))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((perov OR (petruov OR periuov)) OR ((petrouo OR petrui) OR (petro OR petr))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((perov OR (petruov OR periuov)) OR ((petrouo OR petrui) OR (petro OR petr))) o.s.*.