Simplicity 7828 vintage sewing pattern, dated 1977.

A "How to Sew" Pattern, Teen-Boys' Shirt (Including a Lesson Chart..."How to make a shirt collar"):

Shirt with long set-in sleeves and buttoned cuffs or short set-in sleeves has collar, front button closing, slits in side seams and optional pocket.

Size Teen 14:

Chest 32 inches / 81 cm

Pattern is cut and checked complete. Envelope is intact, in good vintage condition.

More children's patterns here:

https://allthepreciousthings.com.au/collections/baby-and-children