Update introduction.tex

AAAI2021/tex/introduction.tex

@@ -72,13 +72,13 @@ vocabulary can express almost infinite concepts.}
   \end{table*}
 
 Prior studies focus on achieving high compositional symbolic language
-through \emph{deliberately handcrafted} inductions, e.g., additional rewards~\cite{},
+through \emph{deliberately handcrafted} inductions, e.g., additional rewards~\cite{mordatch2017emergence},
 constructed loss functions~\cite{kharitonov2019egg}, structural input data~\cite{lazaridou2018emergence,evtimova2018emergent},
 memoryless~\cite{kottur-etal-2017-natural,li2019ease}, and ease-of-teaching~\cite{li2019ease}.
 \note{Such optimization methodologies are driven by the challenges to generate high compositional symbolic without induction in an existing multi-agent environment.}
 
 Figure~\ref{fig:induction} reports the compositionality when training two agents
-in the widely-used listener-speaker referential game~\cite{} for emerging 100
+in the widely-used listener-speaker referential game~\cite{david1969convention} for emerging 100
 languages, and it can be observed that \note{the compositionality
 of emergent language is seldom high (e.g., $<5\%$ for compositionality $>0.99$)
 without any induction. Moreover, varying