The papers from 2013 are available on the TREC notebook page http://trec.nist.gov/pubs/trec22/trec2013.html . This contains all of the TREC tracks (i.e., microblog and crowdsourcing).

You can find other years here http://trec.nist.gov/proceedings/proceedings.html

I know TREC-KBA was (initially) part of Project Archer [1] from the Data Science Research (DSR) group [2] at University of Florida. The group does have a listing of their published and upcoming research papers [3]. Their publications list has links for some, but not all, of the papers. Typically, if you search on the paper title within quotes, and append a simple "filetype:pdf" you'll usually find it somewhere [4].

[1] http://dsr.cise.ufl.edu/?page_id=288

[2] http://dsr.cise.ufl.edu/

[3] http://dsr.cise.ufl.edu/?page_id=16

[4] https://www.google.com/search?num=100&pws=0&safe=off&suggon=...