From the Wikipedia article about Vibranium we know:
It is most known for being used in the construction of Captain America's Shield, the vibranium was of an ultra-resilient vibranium-iron alloy created by Dr. Myron MacLain. The formula has never been reproduced despite numerous attempts.
But in Captain America: Civil War Tony Stark mentioned that Captain's shield was made by his father, Howard stark.
So is the shield made by Dr. MacLain (wikipedia source) or Howard Stark (Civil War movie)?
From the wiki, Vibranium is native to Wakanda, and found in Wakanda. How was Captain America's shield made in the earlier films? Or did the films simply not mention the source of Vibranium used to make Captain's shield?
From the Wikipedia article on Myron MacLain:
Myron MacLain is a fictional character in the Marvel Comics Universe. He is generally credited as the creator of the proto-adamantium alloy that was used to create Captain America's shield and as the creator of adamantium in an effort to re-create the shield.
I guess, there is a movie and comic continuity, and both continuities could be different.
So I think in the movies, the shield was pure Vibranium created by Howard Stark, and in the comics, the shield was made up by an alloy containing Vibranium and was created by the Dr. Myron. Is that right?