Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petriiov (Expand Search), petroiov (Expand Search), periov (Expand Search)
petruov » petrov (Expand Search), pentruov (Expand Search), petriov (Expand Search), petriuov (Expand Search), petrouov (Expand Search), peruov (Expand Search)
petru » pentru (Expand Search), petri (Expand Search), petriu (Expand Search), petrou (Expand Search), peru (Expand Search)
petriouov » petriiouov (Expand Search), petroiouov (Expand Search), periouov (Expand Search)
petrioi » petriioi (Expand Search), petroioi (Expand Search), perioi (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 petruov) OR petriouov) OR ((petru OR petrioi) OR (petr OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petriov OR petruov) OR petriouov) OR ((petru OR petrioi) OR (petr OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petriov OR petruov) OR petriouov) OR ((petru OR petrioi) OR (petr OR peter))) o.s.*.