This pattern is available in the Summer, 2016 issue of Cast-On Magazine, and will be available for individual pdf download in the Summer of 2017.
The shoulder tabs are knit first, then placed onto stitch holders. The back and front stitches are picked up along the selvedge edges of the shoulder tabs and knit separately to the underarms where they are joined for the body. The body is worked in the round from the top down. The sleeve stitches are picked up around the armhole edge, and joined to the held shoulder tab stitches. The sleeve caps are shaped with short-rows, then the sleeve is worked in the round from the underarm to the cuff.