The link to Halloun & Hestenes 1985 no longer seems to be valid, although the 1992 paper still seems to be good.
That was fast. But no, that seems to be an earlier paper, I meant http://generative.edb.utexas.edu/classes/knl2011fall/Halloun_Hestenes_FCI.pdf
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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