Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petruiov (Expand Search), petroiov (Expand Search), periov (Expand Search)
peris » petris (Expand Search), paris (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (Expand Search)
petroi » petruoi (Expand Search), petrooi (Expand Search), peroi (Expand Search), petro (Expand Search), petrov (Expand Search), petrow (Expand Search)
petruoi » petruuoi (Expand Search), petrouoi (Expand Search), peruoi (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (Expand Search)
petrioi » petruioi (Expand Search), petroioi (Expand Search), perioi (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 (peris OR ((petr OR (((petroi OR petruoi) OR petri) OR petrioi)) OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petriov OR (peris OR ((petr OR (((petroi OR petruoi) OR petri) OR petrioi)) OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (petriov OR (peris OR ((petr OR (((petroi OR petruoi) OR petri) OR petrioi)) OR peter))) o.s.*.