Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petriiov (Expand Search), petroiov (Expand Search), periov (Expand Search)
petroov » petrov (Expand Search), petrioov (Expand Search), petrooov (Expand Search), peroov (Expand Search)
petra » petri (Expand Search), petro (Expand Search), petre (Expand Search), petria (Expand Search), petroa (Expand Search), pera (Expand Search)
petria » petri (Expand Search), petris (Expand Search), petriia (Expand Search), petroia (Expand Search), peria (Expand Search)
petru » pentru (Expand Search), petri (Expand Search), petriu (Expand Search), petrou (Expand Search), peru (Expand Search)
petr » petri (Expand Search), petro (Expand Search), per (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 (((petriov OR petroov) OR ((petra OR petria) OR petriov)) OR (petru OR (petr OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petriov OR petroov) OR ((petra OR petria) OR petriov)) OR (petru OR (petr OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petriov OR petroov) OR ((petra OR petria) OR petriov)) OR (petru OR (petr OR peter))) o.s.*.