Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petriiov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
peterov » petrov (Expand Search)
petr » petri (Expand Search), petru (Expand Search), petro (Expand Search)
petruv » petriuv (Expand Search), petruuv (Expand Search), petrouv (Expand Search), petru (Expand Search), petrov (Expand Search)
petriu » petriiu (Expand Search), petruiu (Expand Search), petroiu (Expand Search), petri (Expand Search), petru (Expand Search), petris (Expand Search)
pero » petro (Expand Search), per (Expand Search), pro (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 peterov) OR petr) OR (petruv OR peruv)) OR ((pero OR petriu) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petriov OR peterov) OR petr) OR (petruv OR peruv)) OR ((pero OR petriu) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petriov OR peterov) OR petr) OR (petruv OR peruv)) OR ((pero OR petriu) OR peter)) o.s.*.