Take the tour ×  I am looking for references on Steinmetz
Transform and its relation with Laplace and Fourier Transforms.
There is an Italian Wikipedia page about this topic but with no
references.  share|improve this question add comment  1 Answer
up vote 3 down vote accepted  (Too long for a comment.) I think
the italian Wiki page is wrong. It says the transform "was
conceived by the author in 1893 [probably this text] and exposed
in his treatise Theory and Calculation of Alternating Current
Phenomena four years later."  However, as you can check there is
not a trace in these texts (nor in the others authored by
Steinmetz and available on archive.org) of what Wikipedia calls
"la transformata di Steinmetz" -- i.e. the Fourier isomorphism
$L^2(S^1)\to\ell^2(\mathbf{Z})$ -- which by the way, was written
explicitly much before 1893.  These texts are famous for
introducing complex numbers (in particular the notation
$j=\sqrt{-1}$) into electrical engineering, but my impression is
that naming the transform in St