Perhaps you should try some spelling variations:
peterov » petrov (Expand Search)
petroov » petrov (Expand Search), petruoov (Expand Search), petrooov (Expand Search), peroov (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (Expand Search)
petroou » petruoou (Expand Search), petrooou (Expand Search), peroou (Expand Search)
petruo » petruuo (Expand Search), petrouo (Expand Search), peruo (Expand Search), petru (Expand Search), petro (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (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 ((peterov OR petroov) OR (((petr OR ((petroou OR petroou) OR peter)) OR petruo) OR petri)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((peterov OR petroov) OR (((petr OR ((petroou OR petroou) OR peter)) OR petruo) OR petri)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((peterov OR petroov) OR (((petr OR ((petroou OR petroou) OR peter)) OR petruo) OR petri)) o.s.*.