Family of Nils Sveum

I am trying to sresearch my husband's family tree and it's alittle more difficult to find information abroad. His great grandfather is the starting oint in Norway. His name was Nils Sveum. Nils was the first to come to America (North Dakota). HIs father's name was Johna Sveum and Johna's wife was Karine ?. I know Nils' name is absolutely correct but my husaband's grandmother it trying to find the proper spelling for Johna. The internet has not been kind to the last name of Sveum so I am asking if anyone could give any helpful advice as I start this labor of love for my husband and sons. Location of Sveum farms or anything you believe could be something for me to watch out for. Thank you in advance for any assistance you may have to offer. Additional information: Nils' son was born in North Dakota USA and his name was Lester A. Johnson Sr. Thank you Karen Johnson