Perhaps you should try some spelling variations:
petrov » petro (Expand Search), petruov (Expand Search), petroov (Expand Search), perov (Expand Search)
petruo » petru (Expand Search), petro (Expand Search), petruuo (Expand Search), petrouo (Expand Search), peruo (Expand Search)
petero » peters (Expand Search), petro (Expand Search)
petriiv » petruiiv (Expand Search), petroiiv (Expand Search), periiv (Expand Search)
petroiiv » petruoiiv (Expand Search), petrooiiv (Expand Search), peroiiv (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (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 ((petriiv OR (petroiiv OR petrov)) OR ((petruo OR petero) OR ((petr OR peter) OR petri))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriiv OR (petroiiv OR petrov)) OR ((petruo OR petero) OR ((petr OR peter) OR petri))) o.s.*".