There is a new book, Armfelt available on John Dalmas' web site at:
http://www.johndalmas.com/area/Catalog/
I have no relationship with the author, I'm just a fan of his. Although he has published many books, this appears to be a previously unpublished work. He describes it as a:
"novelized documentary", which I think means that its historically accurate, but told through the eyes of fictional characters????
Dalmas has a preface that he ends with the following two sentences:
Meanwhile, in 1714, a Russian army had overrun Finland. The hard-bitten remains of the Finnish army, commanded by General Karl Gustaf Armfelt, escaped west across the Torne River into northern Sweden.
This story is about that Finnish army, its general, and some unblooded units of Swedish conscripts, in the bitter, final land campaign of the Great Northern War.