Reference the white paper on MPC parameter generation

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

protocol/protocol.tex

@@ -2967,7 +2967,8 @@ format, are:
     4bd498dae0aacfd8e98dc306338d017d9c08dd0918ead18172bd0aec2fc5df82  sprout-verifying.key
 \end{verbatim}
 
-These parameters were obtained by a multi-party computation described in \cite{GitHub-mpc}.
+These parameters were obtained by a multi-party computation described in
+\cite{GitHub-mpc} and \cite{BGG2016}.
 
 
 \needspace{30ex}
@@ -4081,6 +4082,7 @@ The errors in the proof of Ledger Indistinguishability mentioned in
     \item Give definitions of computational binding and computational hiding
           for commitment schemes.
     \item Give a definition of statistical zero knowledge.
+    \item Reference the white paper on MPC parameter generation \cite{BGG2016}.
 \end{itemize}
 
 \introlist

protocol/zcash.bib

@@ -59,6 +59,14 @@ Lecture Notes in Computer Science; Springer, 2013.},
    urldate={2016-09-01}
 }
 
+@misc{BGG2016,
+   author={Sean Bowe and Ariel Gabizon and Matthew Green},
+   title={A multi-party protocol for constructing the public parameters of the {P}inocchio zk-{SNARK}},
+   date={2016-11-24},
+   url={https://github.com/zcash/mpc/blob/master/whitepaper.pdf},
+   urldate={2017-02-11}
+}
+
 @misc{Naka2008,
    author={Satoshi Nakamoto},
    title={Bitcoin:\, {A}\, {P}eer-to-{P}eer\, {E}lectronic\, {C}ash\, {S}ystem},