Perhaps you should try some spelling variations:
petris » petri (Expand Search), petriis (Expand Search), petruis (Expand Search), petrois (Expand Search)
peterov » petrov (Expand Search)
petruo » petru (Expand Search), petro (Expand Search), petriuo (Expand Search), petruuo (Expand Search), petrouo (Expand Search)
petriuo » petriiuo (Expand Search), petruiuo (Expand Search), petroiuo (Expand Search)
petruuiuo » petriuuiuo (Expand Search), petruuuiuo (Expand Search), petrouuiuo (Expand Search)
petr » petri (Expand Search), petru (Expand Search), petro (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 peterov) OR ((petruo OR (petriuo OR petruuiuo)) OR (petr OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petris OR peterov) OR ((petruo OR (petriuo OR petruuiuo)) OR (petr OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petris OR peterov) OR ((petruo OR (petriuo OR petruuiuo)) OR (petr OR peter))) o.s.*.