Perhaps you should try some spelling variations:
petroov » petrov (Expand Search), petruoov (Expand Search), petrooov (Expand Search), peroov (Expand Search)
petruov » petrov (Expand Search), petruuov (Expand Search), petrouov (Expand Search), peruov (Expand Search), petruv (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (Expand Search)
petruio » petruuio (Expand Search), petrouio (Expand Search), peruio (Expand Search)
petruo » petruuo (Expand Search), petrouo (Expand Search), peruo (Expand Search), petru (Expand Search), petro (Expand Search)
petriuo » petruiuo (Expand Search), petroiuo (Expand Search), periuo (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 ((petroov OR petruov) OR ((((petri OR petr) OR petruio) OR (petruo OR petriuo)) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petroov OR petruov) OR ((((petri OR petr) OR petruio) OR (petruo OR petriuo)) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petroov OR petruov) OR ((((petri OR petr) OR petruio) OR (petruo OR petriuo)) OR peter)) o.s.*.