Need help identifying DUX sofa  

And besides the color blue...
And besides the color blue and having four legs, that one is similar to yours how?

Back cushions..
It's not missing back cushions...I'm not seeing 'Dux' however. Are cushions done in latex?

Hey, Krenit! Thanks for the S...
Hey, Krenit! Thanks for the SUPER friendly and warm welcome!
I'm just going off what the dealer told us. They sell quite a bit of Adrian Pearsall sofas, as well as some other miscellaneous designers, so we did believe them when they told us this sofa is Dux. Not trying to make any claims; we just really want to find out more about this sofa! I don't think there's any harm in that. So, I/the dealer might be wrong. Doesn't mean people need to get snotty.
I had assumed that, since a lot of the Duxs I saw online had the same or a very similar back covered by back cushions, that perhaps ours was missing cushions. That was just an assumption I made after coming up empty handed online.
In regards to the seat cushions, I'll have to double check ? but we believe the entire sofa was reupholstered at some point.

Dux
I was just in Portland Oregon and noticed your sofa at Remnant (google Remnant Portland) and they seem pretty sure it's Dux. Check it out.

Clearly they are experts.
Clearly they are experts.

Don't be snotty...
Remnant's a fun shop, they don't pass themselves off as "experts", just fellow enthusiastic collectors. Nice people with good prices, perfect for those of us with great taste and little budgets.
...and hello to Kat and Hazelnut from Bellingham!

There are fewer resources...
There are fewer resources out there documenting Swedish companies and designers. (too bad).
Also Dux is a bit of a complicated company to document as I believe it went by different names occasionally; sometimes was part of the Bra Bohag group of companies; and later the whole group went by Dux. Or some such complicated corporate international mess. All of which is to say that Dux has a more amorphous history than most.
Of course the sofa may well not be Dux/Swedish at all. Maybe you should ask the dealer what the Dux attribution is based on. The dealer may be able to give you something to start with, or it might have been the name nearest to which the dart stuck.
I think your best bet will be to start with some general search terms and use google and bing image search. See if you can find a company or designer whose chairs or sofas look similar. And take it from there. With luck, a good eye, and a LOT of time you may find another marked specimen.

Unless they glossed over...
Unless they glossed over it,it does not mention anything about different company names in their story and says it's a family company started in 1926.
They started a Duxiana store in the 80s.
Maybe you could email them a picture.
http://www.dux.com/About-DUX/

Not being snotty. Just...
Not being snotty. Just questioning credibility.