Perhaps you should try some spelling variations:
petriv » petri (Expand Search), petris (Expand Search), petrov (Expand Search), peteriv (Expand Search), petriiv (Expand Search), petruiv (Expand Search)
peteri » peterdi (Expand Search), peter (Expand Search), petri (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petru (Expand Search)
petruov » peteruov (Expand Search), petriuov (Expand Search), petruuov (Expand Search), petrov (Expand Search)
petruv » peteruv (Expand Search), petriuv (Expand Search), petruuv (Expand Search), petru (Expand Search), petrov (Expand Search)
petriiiuv » peteriiiuv (Expand Search), petriiiiuv (Expand Search), petruiiiuv (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 ((petriv OR peteri) OR (petr OR ((petruov OR (petruv OR petriiiuv)) OR petriv))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriv OR peteri) OR (petr OR ((petruov OR (petruv OR petriiiuv)) OR petriv))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriv OR peteri) OR (petr OR ((petruov OR (petruv OR petriiiuv)) OR petriv))) o.s.*.