Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), petriuov (Expand Search), petruuov (Expand Search), petrouov (Expand Search)
petrui » petri (Expand Search), petru (Expand Search), petriui (Expand Search), petruui (Expand Search), petroui (Expand Search)
petriui » petriiui (Expand Search), petruiui (Expand Search), petroiui (Expand Search)
petriiuo » petriiiuo (Expand Search), petruiiuo (Expand Search), petroiiuo (Expand Search)
petruuo » petriuuo (Expand Search), petruuuo (Expand Search), petrouuo (Expand Search)
petr » petri (Expand Search), petru (Expand Search), petro (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 ((petruov OR (petrui OR petriui)) OR ((petriiuo OR petruuo) OR (petr OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruov OR (petrui OR petriui)) OR ((petriiuo OR petruuo) OR (petr OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruov OR (petrui OR petriui)) OR ((petriiuo OR petruuo) OR (petr OR peter))) o.s.*.