Perhaps you should try some spelling variations:
petriv » petris (Expand Search), petrov (Expand Search), peteriv (Expand Search), petruiv (Expand Search), petroiv (Expand Search)
petroiv » petrov (Expand Search), peteroiv (Expand Search), petruoiv (Expand Search), petrooiv (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petruov » peteruov (Expand Search), petruuov (Expand Search), petrouov (Expand Search), petrov (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
pero » petro (Expand Search), per (Expand Search), pro (Expand Search)
peteru » peter (Expand Search), petru (Expand Search), peters (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 ((petriv OR petroiv) OR (peruo OR ((petr OR ((pero OR petruov) OR peteru)) OR petri))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriv OR petroiv) OR (peruo OR ((petr OR ((pero OR petruov) OR peteru)) OR petri))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriv OR petroiv) OR (peruo OR ((petr OR ((pero OR petruov) OR peteru)) OR petri))) o.s.*.