Probably published in 1960s. In the 1960s the yarn specified came in 20-25g balls; the first two glove/mitt sizes use 2 balls, and the last three take 3 balls in total, although some styles use scraps of other colours.

Comment by raveler:
The mitts with “L” and “R” motifs are made with intarsia, although embroidery might be more appropriate.