Perhaps you should try some spelling variations:
petriiov » petrov (Expand Search), peteriiov (Expand Search), petriiiov (Expand Search), petruiiov (Expand Search)
petriiv » peteriiv (Expand Search), petriiiv (Expand Search), petruiiv (Expand Search)
petroiv » peteroiv (Expand Search), petrioiv (Expand Search), petruoiv (Expand Search)
petriou » peteriou (Expand Search), petriiou (Expand Search), petruiou (Expand Search)
petruov » peteruov (Expand Search), petriuov (Expand Search), petruuov (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petru (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 (((petriiv OR petroiv) OR peteriv) OR ((petriou OR (petruov OR petriiov)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petriiv OR petroiv) OR peteriv) OR ((petriou OR (petruov OR petriiov)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petriiv OR petroiv) OR peteriv) OR ((petriou OR (petruov OR petriiov)) OR petr)) o.s.*.