Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petriiov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
petrou » petru (Expand Search), petro (Expand Search), petrov (Expand Search), petriou (Expand Search), petruou (Expand Search), petroou (Expand Search)
petrouo » petruo (Expand Search), petroo (Expand Search), petrovo (Expand Search), petriouo (Expand Search), petruouo (Expand Search), petroouo (Expand Search)
petruuiov » petriuuiov (Expand Search), petruuuiov (Expand Search), petrouuiov (Expand Search)
petruiui » petriuiui (Expand Search), petruuiui (Expand Search), petrouiui (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 ((petriov OR petruuiov) OR (((petrou OR petruiui) OR petrouo) OR (petr OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petruuiov) OR (((petrou OR petruiui) OR petrouo) OR (petr OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petruuiov) OR (((petrou OR petruiui) OR petrouo) OR (petr OR peter))) o.s.*.