Perhaps you should try some spelling variations:
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petris » peteris (Expand Search), petruis (Expand Search), petrois (Expand Search)
petra » petera (Expand Search), petrua (Expand Search), petroa (Expand Search), petru (Expand Search), petro (Expand Search), petre (Expand Search)
petroe » peteroe (Expand Search), petruoe (Expand Search), petrooe (Expand Search), petrole (Expand Search), petro (Expand Search), petrov (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
peterov » petrov (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 (petris OR (peterov OR ((petra OR petroe) OR petri)))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petr OR (petris OR (peterov OR ((petra OR petroe) OR petri)))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (petr OR (petris OR (peterov OR ((petra OR petroe) OR petri)))) o.s.*.