The October 1939 issue of Valley Progress magazine with an in-depth article on the new Walt Disney Studio in Burbank. This issue featured a great cover illustration of the so-called "fab five" showing off their new digs. The magazine's accompanying article can be read here.
The same illustration used in an advertisement that appeared in a 1941 - 1942 RKO exhibitor's booklet. The only difference, as pointed out by loyal blog reader and ardent observer Are Myklebust, is that Donald's head has been rotated to the right.
If anyone has an extra copy of Valley Progress for sale, please let me know. I have a friend who is looking for a copy for their collection. Thanks!