Cognomen Janca (Janca 
) , all around the world, is quite a rare surname. The cognomen Janca is characteristic of Czechia, where it is quite a common surname, Albania, where it is quite a rare surname, and Serbia. Not in comparison with a country's population, it is commonest in Czechia, the United States, and Serbia. Much less frequently, Janca is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Janca | Serbia, Czechia, India, Poland, United States |
| jan janca German organist and composer, DE (b. 1933) |
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| radek janca researcher |
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| emilia k janca researcher (ORCID 0000-0001-9679-4893) |
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