Perhaps you should try some spelling variations:
petrov » petro (Expand Search), petruov (Expand Search), petroov (Expand Search), perov (Expand Search)
petrv » petru (Expand Search), petro (Expand Search), petra (Expand Search), petruv (Expand Search), petrov (Expand Search), perv (Expand Search)
petrou » petru (Expand Search), petro (Expand Search), petruou (Expand Search), petroou (Expand Search), perou (Expand Search)
petrow » petro (Expand Search), petrowna (Expand Search), petruow (Expand Search), petroow (Expand Search), perow (Expand Search)
petroov » petruoov (Expand Search), petrooov (Expand Search), peroov (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (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 ((petrov OR ((petrv OR petroov) OR petri)) OR ((petrou OR petrow) OR (petr OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petrov OR ((petrv OR petroov) OR petri)) OR ((petrou OR petrow) OR (petr OR peter))) o.s.*".