Help writing an essay - citations

Hey guys,

I want to write an essay/paper but I'm not entirely sure how to go about citations. I'm familiar with how they are supposed to work but have never properly written a paper using them. For example:

From wikipedia:
As a general theory of dynamics, Lorentz and Poincare had already (by about 1905) found it necessary to invoke the principle of relativity itself in order to make the theory match all the available empirical data. By this point, most vestiges of a substantial ether had been eliminated from Lorentz's "ether" theory, and it became both empirically and deductively equivalent to special relativity. The main difference was the metaphysical postulate of a unique absolute rest frame, which was empirically undetectable and played no role in the physical predictions of the theory, as Lorentz wrote in 1909,[C 7] 1910 (published 1913),[C 8] 1913 (published 1914),[C 9] or in 1912 (published 1922).[C 10]

Excerpt: In the above it says that "by this time, most vestiges of a substantial ether had been eliminated....the main difference...postulate of a unique absolute rest frame..."

Now, the references they cite in the wiki article don't explicitly say that LET can be formulated without an ether but relies on an absolute reference frame, the excerpt I focus on is obviously the conclusion that someone draws from those articles. If I want to state that:
"LET can be formulated without an ether but relies on an absolute reference frame", how could I reference that?

https://en.m.wikipedia.org/wiki/Lorentz_ether_theory#Later_activity