Perhaps you should try some spelling variations:
petris » petri (Expand Search), petriis (Expand Search), petruis (Expand Search), petrois (Expand Search)
petroiv » petrov (Expand Search), petrioiv (Expand Search), petruoiv (Expand Search), petrooiv (Expand Search)
peters » petersen (Expand Search)
petruiv » petriuiv (Expand Search), petruuiv (Expand Search), petrouiv (Expand Search)
petriou » petriiou (Expand Search), petruiou (Expand Search), petroiou (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 (((petris OR petroiv) OR petruiv) OR ((petriou OR peters) OR (petr OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petris OR petroiv) OR petruiv) OR ((petriou OR peters) OR (petr OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petris OR petroiv) OR petruiv) OR ((petriou OR peters) OR (petr OR peter))) o.s.*.