Am I right that this form was used to consolidate information from disparate sources into a common format? So this box "Information Obtained From--" would be coded according to the original source or sources the compiler was working from? I don't suppose there's a master index somewhere showing a list of such original sources?
I do notice a code from your second example form that reminds me of the CYB from the other one:
View attachment 406775
Looks as if it says something like "C_B" -- not sure what the middle character or characters represents...
R