Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petriiov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
petrouv » petrov (Expand Search), petriouv (Expand Search), petruouv (Expand Search), petroouv (Expand Search)
peters » petersen (Expand Search)
petriuv » petriiuv (Expand Search), petruiuv (Expand Search), petroiuv (Expand Search)
petr » petri (Expand Search), petru (Expand Search), petro (Expand Search)
petriuiui » petriiuiui (Expand Search), petruiuiui (Expand Search), petroiuiui (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 ((petriov OR (petrouv OR petriuv)) OR (peters OR ((petr OR petriuiui) OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR (petrouv OR petriuv)) OR (peters OR ((petr OR petriuiui) OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR (petrouv OR petriuv)) OR (peters OR ((petr OR petriuiui) OR peter))) o.s.*.