32 mentions are found for request
different sources from the year —1917 (6) 1923 (12) 1924—1938 (9) 1942—2007 (5)

Jan Slobodan Kreber

Source: 'Encyclopaedia of Croatian Surnames , year 2007.

Jan Vavra

Source: 'Encyclopaedia of Croatian Surnames , year 2007.