Perhaps you should try some spelling variations:
petruv » petrov (Expand Search), pentruv (Expand Search), petrouv (Expand Search), peruv (Expand Search)
petru » pentru (Expand Search), petrou (Expand Search), peru (Expand Search)
petroov » petrov (Expand Search), petrooov (Expand Search), peroov (Expand Search)
petr » petro (Expand Search), per (Expand Search)
petri » petroi (Expand Search), peri (Expand Search)
petris » petrois (Expand Search), peris (Expand Search)
petrois » petroois (Expand Search), perois (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 ((((petruv OR petru) OR petroov) OR ((petr OR petri) OR (petris OR petrois))) OR peter) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petruv OR petru) OR petroov) OR ((petr OR petri) OR (petris OR petrois))) OR peter) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petruv OR petru) OR petroov) OR ((petr OR petri) OR (petris OR petrois))) OR peter) o.s.*.