Perhaps you should try some spelling variations:
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petruov » peteruov (Expand Search), petriuov (Expand Search), petruuov (Expand Search)
petrv » peterv (Expand Search), petriv (Expand Search), petruv (Expand Search)
petruv » peteruv (Expand Search), petriuv (Expand Search), petruuv (Expand Search)
petriuv » peteriuv (Expand Search), petriiuv (Expand Search), petruiuv (Expand Search)
petruiv » peteruiv (Expand Search), petriuiv (Expand Search), petruuiv (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 ((((petriov OR petruov) OR ((petrv OR petruv) OR petriuv)) OR petruiv) OR petr) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petriov OR petruov) OR ((petrv OR petruv) OR petriuv)) OR petruiv) OR petr) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petriov OR petruov) OR ((petrv OR petruv) OR petriuv)) OR petruiv) OR petr) o.s.*.