Knelske Johannes Apol, born in Sauwerd circa 1849.

She was married to
Klaas Derks Zwartsenberg, born in Groningen circa 1852.

• 1 : Johanna, born in Obergum (gem Winsum) on December 25, 1875, died in Winsum on June 1, 1957, buried in Winsum-Obergum.
  She was married in Winsum on May 14, 1898 to Marten Maring, born in Tinallinge (gem Baflo) on July 6, 1873, died in Winsum on July 2, 1945, buried in Winsum-Obergum, son of Harm Maring and Aafke Poel.