Perhaps you should try some spelling variations:
petriiov » petrov (Expand Search), peteriiov (Expand Search), petruiiov (Expand Search), petroiiov (Expand Search)
petriov » peteriov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
petruov » peteruov (Expand Search), petruuov (Expand Search), petrouov (Expand Search)
petroiv » peteroiv (Expand Search), petruoiv (Expand Search), petrooiv (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (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 (petriiov OR petruov)) OR petroiv) OR ((pero OR petri) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petriov OR (petriiov OR petruov)) OR petroiv) OR ((pero OR petri) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petriov OR (petriiov OR petruov)) OR petroiv) OR ((pero OR petri) OR petr)) o.s.*.