Perhaps you should try some spelling variations:
petr » peter (Expand Search), petro (Expand Search), per (Expand Search)
petru » peteru (Expand Search), petrou (Expand Search), peru (Expand Search), pentru (Expand Search)
petrv » peterv (Expand Search), petrov (Expand Search), perv (Expand Search), petro (Expand Search), petra (Expand Search)
petris » peteris (Expand Search), petrois (Expand Search), peris (Expand Search)
petri » peteri (Expand Search), petroi (Expand Search), peri (Expand Search)
peters » peter (Expand Search), petersen (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 (peters OR (petru OR peters))) OR petrv) OR petris) OR petri) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petr OR (peters OR (petru OR peters))) OR petrv) OR petris) OR petri) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petr OR (peters OR (petru OR peters))) OR petrv) OR petris) OR petri) o.s.*.