There are small hints in each sentence that indicate their sequence.
A cannot be the first in the sequence as, “documents like these indicating”, indicates that this statement follows another.
B cannot be the first either as, “pursued similar “border scientific” doctrines”, indicates that if follows another statement.
Now, between C and D, we can see that C talks about 1933 and D talks about mid-1930s.
This implies C precedes D.
Therefore, C is the first statement.
D precedes B, as D talks about “how Hitler’s second in chief sponsored astrology, “cosmobiology,” and other esoteric medical practices” and B starts with “Hitler’s chief of the SS, Heinrich Himmler, pursued similar “border scientific” doctrines.”
The word similar indicates that an instance similar to the one mentioned in D is being described in B.
“Hundreds of archival documents like these indicate ..” in A implies that, A follows B as “these” refers to “doctrines” mentioned in B.
Therefore, the order is CDBA.