I Cartan's Understanding of Einstein Field Equation

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Cartan and general relativity
About a week ago I was reading about Cartan's geometric interpretation of the Einstein Field Equation

Gij + Λgij = κTij

According to Cartan, this equation expresses the idea

(sum of moments of rotation for the faces of a little 3-cube) = 8π * (amount of energy-momentum within that 3-cube)

As far as I can tell, it is only in John Wheeler's various books (MTW, but also his other books) where this idea of Cartan is explained. None of the other popular books like Wald discuss this. Apparently, it was Wheeler who dug it out of Cartan's papers and made it widely known. If anyone on this forum has a good understanding of this, I would appreciate it if you can share/explain this. Also, why don't more people and books adopt this viewpoint? Is it because Cartan's coordinate free differential geometry is too sophisticated?
 
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Frankly I don't know why...Btw MTW has also a section for the Cartan's geometric interpretation of Newton spacetime (basically the Poisson equation).
 
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