Tyler Sterling

Hello Elk developers: Firstly, thanks for the very cool code. I was wondering if there is any technical document describing the implementation of DFPT for phonons in Elk? I am trying to figure out how to do some modification of my own and I poured through the source code, but without some literature to look at, I am not entirely sure what Elk is doing in all places. I looked at some of the FP-LAPW papers on DFPT (e.g. PhysRevB.64.184306) but I don't know which one is most closely related to Elk....