Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petroiov (Expand Search), periov (Expand Search)
petrouv » petrov (Expand Search), petroouv (Expand Search), perouv (Expand Search)
petra » petro (Expand Search), petre (Expand Search), petroa (Expand Search), pera (Expand Search)
petroiv » petrov (Expand Search), petrooiv (Expand Search), peroiv (Expand Search)
petri » petroi (Expand Search), peri (Expand Search)
petr » petro (Expand Search), per (Expand Search)
petru » petrou (Expand Search), peru (Expand Search), pentru (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 ((((petri OR petriov) OR petrouv) OR (petra OR petroiv)) OR ((petr OR petru) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petri OR petriov) OR petrouv) OR (petra OR petroiv)) OR ((petr OR petru) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petri OR petriov) OR petrouv) OR (petra OR petroiv)) OR ((petr OR petru) OR peter)) o.s.*.