Hi, Can't find anything on Gustaf and Linnea, but found Dufvas near Water Glen in these two books on-line.
http://www.ourroots.ca/e/toc.aspx?id=7543 The main bio is in volume 2.
http://www.ourroots.ca/e/toc.aspx?id=7544 Do a Dufva search in the books and click on the page numbers that show up. You can also use the arrows at the top or bottom of the page to change. Butch (board volunteer)