Perhaps you should try some spelling variations:
petriiov » petrov (Expand Search), peteriiov (Expand Search), petriiiov (Expand Search), petruiiov (Expand Search)
petruoov » petrov (Expand Search), peteruoov (Expand Search), petriuoov (Expand Search), petruuoov (Expand Search)
petrioiov » peterioiov (Expand Search), petriioiov (Expand Search), petruioiov (Expand Search)
petruui » peteruui (Expand Search), petriuui (Expand Search), petruuui (Expand Search)
petruov » peteruov (Expand Search), petriuov (Expand Search), petruuov (Expand Search)
petroov » peteroov (Expand Search), petrioov (Expand Search), petruoov (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 ((petriiov OR petrioiov) OR ((petruui OR (petruov OR (petroov OR petruoov))) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriiov OR petrioiov) OR ((petruui OR (petruov OR (petroov OR petruoov))) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriiov OR petrioiov) OR ((petruui OR (petruov OR (petroov OR petruoov))) OR petr)) o.s.*.