If you want a couple of websites to back up the scan:
http://www.marvunapp.com/Appendix2/maclainmyron.htm
http://en.wikipedia.org/wiki/Captain_America's_shield
Rogers' indestructible shield has often been referred to as being an adamantium-vibranium alloy. This is not the case: adamantium was only developed after Rogers was revived from suspended animation, during MacLain's later experiments to try and duplicate the material of the shield (the substance made its first appearance in Avengers Vol. 1 #66, July 1969).The adamantium-vibranium error first arose in the Captain America entry in the Official Handbook of the Marvel Universe (the composition of the shield was accurately described in the adamantium entry) and was propagated in several subsequent stories by writers using the Handbook as a reference. The error was corrected in "Captain America" #303-304, in 1983, which established that the shield is made of vibranium and steel, but that didn't prevent the error's repetition over the years.
(So I was off by an issue or two. It's CA #303 or 304.)
Also from marveldirectory:
http://www.marveldirectory.com/miscellaneous/adamantium.htm
MacLain began experimenting with the process that created Adamantium as a young scientist in the employ of the United States government in the early 1940s. Assigned to create a super-metal with which to build tanks, MacLain labored for month, experimenting with various iron alloys. One of his experiments utilized the rare meteoric ore now known as Wakandan Vibranium. He tried to fuse the Vibranium to the iron alloy numerous times without success. Then one night when he dozed off, some as yet unknown factor entered the process, and permitted the fusion to occur. Upon discovering his success, MacLain poured the molten metal into a disc-shaped mold. The disc, once solidified, has proven to be the most impervious object ever created on Earth. MacLain turned the discover to the government and it was given to Captain America to use as his shield. Neither MacLain nor anyone else has ever been able to discover what was the x-factor that entered the process, or has been able to fuse Vibranium with another metal. (The unknown iron-Vibranium alloy of which the shield is composed resembles True Adamantium, although Adamantium itself contains no Vibranium,)