Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petriiov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
petriv » petri (Expand Search), petris (Expand Search), petrov (Expand Search), petriiv (Expand Search), petruiv (Expand Search), petroiv (Expand Search)
petria » petri (Expand Search), petris (Expand Search), petriia (Expand Search), petruia (Expand Search), petroia (Expand Search)
petra » petri (Expand Search), petru (Expand Search), petro (Expand Search), petria (Expand Search), petrua (Expand Search), petroa (Expand Search)
petroov » petrov (Expand Search), petrioov (Expand Search), petruoov (Expand Search), petrooov (Expand Search)
petr » petri (Expand Search), petru (Expand Search), petro (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 ((petriv OR (petria OR petra)) OR petroov)) OR (petriov OR (petr OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR ((petriv OR (petria OR petra)) OR petroov)) OR (petriov OR (petr OR peter))) o.s.*".