Perhaps you should try some spelling variations:
perov » petrov (Expand Search)
petruiov » petrov (Expand Search), peteruiov (Expand Search), petruuiov (Expand Search), peruiov (Expand Search)
petro » petrov (Expand Search), petru (Expand Search), petero (Expand Search), petruo (Expand Search), pero (Expand Search)
petriov » peteriov (Expand Search), petruiov (Expand Search), periov (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), peri (Expand Search)
petr » peter (Expand Search), petru (Expand Search), per (Expand Search)

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: fop ((perov OR ((petriov OR petruiov) OR petruiov)) OR ((petro OR petri) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((perov OR ((petriov OR petruiov) OR petruiov)) OR ((petro OR petri) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((perov OR ((petriov OR petruiov) OR petruiov)) OR ((petro OR petri) OR petr)) o.s.*.