I did this oil painting of Stegosaurus vs. Ceratosaurus around the 6th grade. It was copied from a (much better!) Charles R. Knight painting published in the February, 1942 issue of National Geographic Magazine, a copy of which is also in my collection).
One of a “Dinosaur Series” of trading cards issued by Nu-Cards in 1961, this one reproducing Knight’s painting but sans color. The cards came with bubble gum, long since extinct.