Perhaps you should try some spelling variations:
petroiov » petrov (Expand Search), peteroiov (Expand Search), petrioiov (Expand Search), petruoiov (Expand Search)
peteruio » peterdi (Expand Search)
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petruou » peteruou (Expand Search), petriuou (Expand Search), petruuou (Expand Search)
petriv » peteriv (Expand Search), petriiv (Expand Search), petruiv (Expand Search)
petruiv » peteruiv (Expand Search), petriuiv (Expand Search), petruuiv (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petru (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 petroiov) OR (((peteruio OR petruou) OR (petriv OR petruiv)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petroiov) OR (((peteruio OR petruou) OR (petriv OR petruiv)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petroiov) OR (((peteruio OR petruou) OR (petriv OR petruiv)) OR petr)) o.s.*.