Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petriiov (Expand Search), petroiov (Expand Search), periov (Expand Search)
petr » petri (Expand Search), petro (Expand Search), per (Expand Search)
petris » petriis (Expand Search), petrois (Expand Search), peris (Expand Search), petri (Expand Search)
petrois » petriois (Expand Search), petroois (Expand Search), perois (Expand Search)
petrou » petriou (Expand Search), petroou (Expand Search), perou (Expand Search), petro (Expand Search), petrov (Expand Search), petrow (Expand Search)
petru » petriu (Expand Search), petrou (Expand Search), peru (Expand Search), pentru (Expand Search), petri (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 ((peroov OR petriov) OR ((petr OR ((petris OR petrois) OR (petrou OR petru))) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((peroov OR petriov) OR ((petr OR ((petris OR petrois) OR (petrou OR petru))) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((peroov OR petriov) OR ((petr OR ((petris OR petrois) OR (petrou OR petru))) OR peter)) o.s.*.