I bought this Portuguese magazine about 15 years ago. At the time I did not know much about most of the best Disney artists, aside from a few of the Nine Old Men. So while I liked the cover, I did not pay very close attention to it.
It wasn't until I met John Canemaker in New York two weeks ago and he showed me the illustrations for his upcoming book on Joe Grant and Joe Ranft that I realized the obvious: this cover was created by Joe Grant. It is even signed in the top right corner. That was an embarassing but very enjoyable "Aha!" moment.