Perhaps you should try some spelling variations:
petr » peter (Expand Search), petri (Expand Search), petru (Expand Search)
petroi » peteroi (Expand Search), petrioi (Expand Search), petruoi (Expand Search), petri (Expand Search), petro (Expand Search), petrov (Expand Search)
petrui » peterui (Expand Search), petriui (Expand Search), petruui (Expand Search), petri (Expand Search), petru (Expand Search)
petriv » peteriv (Expand Search), petriiv (Expand Search), petruiv (Expand Search), petri (Expand Search), petrov (Expand Search)
petris » peteris (Expand Search), petriis (Expand Search), petruis (Expand Search), petri (Expand Search)
petruois » peteruois (Expand Search), petriuois (Expand Search), petruuois (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 (petr OR ((petroi OR petrui) OR (petriv OR (petris OR petruois)))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petr OR ((petroi OR petrui) OR (petriv OR (petris OR petruois)))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (petr OR ((petroi OR petrui) OR (petriv OR (petris OR petruois)))) o.s.*.