added pointer to:

- Birgit Richter,
*Commutative ring spectra*(arXiv:1710.02328)

Took the liberty of adding this to the list of references for homotopy-commutative ring spectra:

]]>What’s actually the *original* reference on the concept of (homotopy commutative) rind spectra, if any?

In Adams 74 it says on p. 246, without citation:

G.W. Whitehead introduced the notion of a ring spectrum

Is this meant to acknowledge private communication, or is there a publication by Whitehead that could be cited here?

]]>added DOI to

- R. Bruner, Peter May, James McClure, M. Steinberger,
*$H_\infty$-Ring Spectra and their Applications*, Lecture Notes in Mathematics 1176, Springer 1986 (doi:10.1007/BFb0075405, pdf)

noticed that the Idea-section at *ring spectrum* didn’t at all address the evident subtlety here. Have expanded now to make this clear.