Perhaps you should try some spelling variations:
petruuov » petrov (Expand Search), peteruuov (Expand Search), petriuuov (Expand Search), petruuuov (Expand Search)
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petruv » peteruv (Expand Search), petriuv (Expand Search), petruuv (Expand Search)
petruuv » peteruuv (Expand Search), petriuuv (Expand Search), petruuuv (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 petruuov) OR ((petruv OR petruuv) OR peteriuv)) OR petruiv) OR petr) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petriov OR petruuov) OR ((petruv OR petruuv) OR peteriuv)) OR petruiv) OR petr) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petriov OR petruuov) OR ((petruv OR petruuv) OR peteriuv)) OR petruiv) OR petr) o.s.*.