Hans Johannesen - Parentage of Berith's Children

What is the proof that Hans and Berith had Anne, Johannes, and Tron? From the parish baptism records:

Birth Baptism Name Married Parents? Parent's names
21.12.1830 16.1.1831 Anne Unmarried Hans Olsen Ri(k)ssad and Beret Tronsdtr Dovresodegaarden
https://www.digitalarkivet.no/kb20070603940150

11.2.1833 24.3.1833 Johannes Unmarried Berit Trondsd. Dovresodegaarden and Hans Olss. Rissad af Land.
https://www.digitalarkivet.no/kb20070603940173

8.12.1837 21.1.1838 Trond Unmarried Hans Johanssen, Ranoms Fr. and Beret Tronsdatter
https://www.digitalarkivet.no/kb20070603920249

It seems as though Anne and Johannes are full siblings, but they only share a mother with Tron. Thoughts?