Perhaps you should try some spelling variations:
petrov » peterov (Expand Search), petriov (Expand Search), petroov (Expand Search)
petroov » peteroov (Expand Search), petrioov (Expand Search), petrooov (Expand Search)
petriv » peteriv (Expand Search), petriiv (Expand Search), petroiv (Expand Search)
petruv » peteruv (Expand Search), petriuv (Expand Search), petrouv (Expand Search)
petru » peteru (Expand Search), petriu (Expand Search), petrou (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petro (Expand Search)

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: fop ((petrov OR petroov) OR ((((peterov OR petriv) OR petruv) OR petruv) OR (petru OR petr))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petrov OR petroov) OR ((((peterov OR petriv) OR petruv) OR petruv) OR (petru OR petr))) o.s.*".