A sweater and pants outfit for Barbie.
Pants are not shown in the picture.

Sweater is worked flat in one piece. First front is worked from the bottom up, then some stitches are bound off and casted on the following row to make the neckhole, and the back is worked from the top down. The arms are picked up from the sides and knitted to the cuff. Finally underarms and sides are sewn.

Pants are worked flat one leg at a time, then legs are joined at the crotch and worked in one piece to the waist. Finally the legs and the center back are sewn.
Pattern doesn’t specify it, but colorwork technique required is (most probably) intarsia.

Look for pattern by number at http://www.stickatillbarbie.se.
The website is in English & Swedish, but patterns are available in several languages.

On the website you’ll find the patterns listed on the left, by number, grouped on pages.
Accessories like hats, scarves or bags are listed in the accessory section, below in the left column.
Click on numbers to open a page, look for the numbered image, then for the link to the desired language below it (clicking on the image will only enlarge it).

This pattern comes in a .doc file.

No specific yarn or gauge is given in the pattern.
Sticka till Barbie patterns are usually designed for 4 ply mercerized cotton yarn or other fingering yarn, and gauge for stockinette stitch is given in the yarn page of the site.