Knit your own Polo Dickey using these clearly-written instructions by knitwear designer Jackie E-S of HeartStrings FiberArts.
Polo Dickey is a versatile sweaterette suitable for wearing under V-neck sweaters, open-necked shirts, etc. A dickey is just right for occasions when an entire shirt under a sweater would be too much. Yet you need a little bit of extra warmth, or you want the look of layered fashion without the extra layers. Directions are included for both men's and women's styles of button plackets.
Preview sample cover page

Instructions for 2 sizes: Smaller (up to 15½” neck) and Larger (up to 18½” neck).
DK weight yarn: 155 [185] yards main color, 70 [85] yards contrast color. Size US 5 / 3.75 mm needles suggested or size to give gauge of 5½ stitches per inch over stockinette stitch, plus needles one size smaller and one size larger than those used to obtain gauge. Written stitch instructions.
Sample of women's style was knitted in Lorna's Laces Swirl, colors Vera (main color) and Berry (contrast color). Men's style (blue) was knitted in Steinbach Wolle Supersport colors 58 and 105.