Perhaps you should try some spelling variations:
petriv » petri (Expand Search), petris (Expand Search), petrov (Expand Search), petriiv (Expand Search), petruiv (Expand Search), petroiv (Expand Search)
petrovv » petrov (Expand Search), petriovv (Expand Search), petruovv (Expand Search), petroovv (Expand Search)
petriu » petri (Expand Search), petru (Expand Search), petris (Expand Search), petriiu (Expand Search), petruiu (Expand Search), petroiu (Expand Search)
petruou » petriuou (Expand Search), petruuou (Expand Search), petrouou (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 ((petriv OR petrovv) OR ((petruou OR petriu) OR (petr OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriv OR petrovv) OR ((petruou OR petriu) OR (petr OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriv OR petrovv) OR ((petruou OR petriu) OR (petr OR peter))) o.s.*.