BibTeX: 
@article{KAT_and_DRAAFP,
author = {Alasdair Armstrong and Victor B. F. Gomes and Georg Struth},
title = {Kleene Algebra with Tests and Demonic Refinement Algebras},
journal = {Archive of Formal Proofs},
month = jan,
year = 2014,
note = {\url{http://isaafp.org/entries/KAT_and_DRA.html},
Formal proof development},
ISSN = {2150914x},
}
