[MarkSheppard]

DRG....

Have some more:

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https://collections.nlm.nih.gov/?utf...+Laboratory%22

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https://collections.nlm.nih.gov/cata...d-101677644-bk
Visual requirements for spotting
Armored Medical Research Laboratory, February 20, 1943

But this is more important:

https://collections.nlm.nih.gov/cata...d-101677966-bk
and
https://collections.nlm.nih.gov/cata...d-101677968-bk

First AND Second partial reports on Project no. 21, Determination of the sources, magnitude, and costs of gunnery errors