Perhaps you should try some spelling variations:
petris » peteris (Expand Search), petruis (Expand Search), petrois (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petruov » peteruov (Expand Search), petruuov (Expand Search), petrouov (Expand Search), petrov (Expand Search)
petruv » peteruv (Expand Search), petruuv (Expand Search), petrouv (Expand Search), petru (Expand Search), petrov (Expand Search)
petruuv » peteruuv (Expand Search), petruuuv (Expand Search), petrouuv (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (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 (petris OR ((petr OR ((petruov OR petris) OR (petruv OR petruuv))) OR petri)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petris OR ((petr OR ((petruov OR petris) OR (petruv OR petruuv))) OR petri)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (petris OR ((petr OR ((petruov OR petris) OR (petruv OR petruuv))) OR petri)) o.s.*.