For those starting to see damage from winterkill, University of Nebraska just posted a comprehensive winterkill guide at http://turf.unl.edu/ .

This publications covers everything from the how’s and why’s of winterkill; reseeding strategies; choosing species/mixes for reseeding; controlling Poa in seedling turf; and much more.

The exact link is http://turf.unl.edu/2014MarchCompWinterkill.pdf but they have much more information on winterkill and other turf management aspects on the rest of their web page at http://turf.unl.edu/  .