I am looking for information regarding Jürgan Gerhard ONKEN and his family who resided in Fedderwarden, Oldenbürg, Germany in the early 1900's.

He married Gratja RADEMACHER, and either he or she re-married as I am aware that Jürgan's son, Hinrich Gerhard ONKEN, had half-siblings. Jürgan died in Heidmühle, Schortens, Oldenbürg, Germany.

Hinrich Gerhard was born 4/29/1881 in Heidmühle, Schortens, Oldenbürg, Germany. He married Rieke Tiebbend SIEBELS, daughter of Johann Hinrich SIEBELS and Louisa Maria Henrietta Wilhelmina REINERS. Rieke was born 3/26/1886 in Belfast?, Bant, Rüstringen, Oldenbürg, Germany.

They came to Illinois in the summer of 1910 and moved to Minnesota in 1912.

I have information on Hinrich and Rieke's children, but I would like more information on their parents and siblings/half-siblings.