Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petriiov (Expand Search), petroiov (Expand Search), periov (Expand Search)
petriv » petri (Expand Search), petrov (Expand Search), petriiv (Expand Search), petroiv (Expand Search), periv (Expand Search)
petroiv » petrov (Expand Search), petrioiv (Expand Search), petrooiv (Expand Search), peroiv (Expand Search)
petris » petri (Expand Search), petriis (Expand Search), petrois (Expand Search), peris (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 periov) OR ((petriv OR petroiv) OR petris)) OR ((petru OR petr) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petriov OR periov) OR ((petriv OR petroiv) OR petris)) OR ((petru OR petr) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petriov OR periov) OR ((petriv OR petroiv) OR petris)) OR ((petru OR petr) OR peter)) o.s.*.