This is a wonderful review article on the issue of the bosonic mode that couples to the quasiparticle in the cuprate superconductors. Deciphering the nature of this boson is THE key issue in the mechanism of superconductivity for this family of material. This article compiles the relevant experimental data from angle-resolved photoemission spectroscopy (ARPES), optical measurement, and tunneling spectroscopy, to present the state of knowledge about this bosonic mode.
What makes this article even more useful is that, if you're not familiar with the physics surrounding these techniques, especially for ARPES and optical conductivity, it provides a nice brief summary of these techniques and what they actually measure that can provide the information needed.
A highly useful article, in more ways than one.