Peter (PW) Hackanson

I am looking for more information about three children of PW and Hanna Hackanson.

Both Peter and Hanna were born in Sweden, and lived near Swedeburg,Saunders County, Nebraska in the late 1800's to early
1900's.

The children I need more information on are:
Anna Hackanson-Ringstrom - B/D - unknown
Olaf P. Hackanson - B 2/26/1872, D 10/14/1907
Hannah - B 4/26/1879 D 5/22,1951

PW and Hannah had two other children, Else Hackanson Olson, who was my GG Grandmother, and a son Nels.

I have information about Nels, but am lacking information about the remaining family.

Thanks for any help you can give me.