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