Enjoy this free pattern courtesy Makers' Mercantile. Read the original blog post HERE. The sample was knit with 6 balls Zitron Gesa & Flo held double throughout. Note that knitting with a single strand of Gesa & Flo will not give you a sweater of the desired size.
You may substitute any yarn that will give you the indicated gauge and a fabric that makes you happy. Worsted weight yarns are a good bet; you might also test sport weight and aran weight yarns to see if they will work–yarn weights are notoriously shifty.