Perhaps you should try some spelling variations:
petriov » petrov (Expand Search)
petroov » petrov (Expand Search)
petrv » petrov (Expand Search), petri (Expand Search), petr (Expand Search)
petroa » petro (Expand Search), petrov (Expand Search), petra (Expand Search)
petriv » petri (Expand Search), petris (Expand Search), petrov (Expand Search)
petrou » petro (Expand Search), petrov (Expand Search), petrow (Expand Search)
petru » pentru (Expand Search), petri (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 (((petriov OR petroov) OR ((petrv OR petroa) OR petriv)) OR (petrou OR (petru OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petriov OR petroov) OR ((petrv OR petroa) OR petriv)) OR (petrou OR (petru OR peter))) o.s.*".