Fixed missing reference

Sections/10_Introduction.tex

@@ -17,12 +17,14 @@ design of these control schemes, as the results could vary greatly from one
 implementation to another.
 
 Gaussian Processes have been previously used to model building dynamics, but
-they are usually limited by a fixed computational budget. This limits the
-approaches that can be taken for identification and update of said models.
-Learning \acrshort{gp} models have also been previously used in the context of
-autonomous racing cars \cite{kabzanLearningBasedModelPredictive2019}, but there
-the Sparse \acrshort{gp} model was built on top of a white-box model and only
-responsible for fitting the unmodeled dynamics. 
+they are usually limited by a fixed computational
+budget~\cite{jainLearningControlUsing2018,nghiemDatadrivenDemandResponse2017}.
+This limits the approaches that can be taken for identification and update of
+said models.  Learning \acrfull{gp} models have also been previously used in
+the context of autonomous racing cars
+\cite{kabzanLearningBasedModelPredictive2019}, but there the Sparse
+\acrshort{gp} model was built on top of a white-box model and only responsible
+for fitting the unmodeled dynamics.
 
 \subsection{Previous Research}
 With the increase in computational power and availability of data  over time,