Perhaps you should try some spelling variations:
petra » petru (Expand Search), petro (Expand Search), petre (Expand Search), petrua (Expand Search), petroa (Expand Search), pera (Expand Search)
petris » petruis (Expand Search), petrois (Expand Search), peris (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (Expand Search)
petrou » petruou (Expand Search), petroou (Expand Search), perou (Expand Search), petru (Expand Search), petro (Expand Search)
petrov » petruov (Expand Search), petroov (Expand Search), perov (Expand Search), petro (Expand Search)
petrow » petruow (Expand Search), petroow (Expand Search), perow (Expand Search), petro (Expand Search), petrowna (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (Expand Search)

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 ((petra OR peter) OR petr)) OR ((petrou OR (petrov OR petrow)) OR petri)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petris OR ((petra OR peter) OR petr)) OR ((petrou OR (petrov OR petrow)) OR petri)) o.s.*".