Looking for records of Smata and/or Cervinka

Looking for ancestry records for great-grandparents Amon and Ana (Cervinka) Smata, and grandmother Agnes (Anuska) Smata (born 1906). Place of birth Okucani, Croatia? 1912 passenger list from ship passage shows their place of origin as Bohemia. Wanting to dig deeper into their ancestry and places of origin/where they lived in Europe.