arXiv:1303.7108 A classification of small homotopy functors from spectra to spectra fra arXiv Front: math.AT av Boris Chorny We show that every small homotopy functor from spectra to spectra is weakly equivalent to a filtered colimit of representable functors represented in cofibrant spectra. Moreover, we present this classification as a Quillen equivalence of the category of small functors from spectra to spectra equipped with the homotopy model structure and the opposite of the pro-category of spectra with the strict model structure.
nLab page on Spectrum II