Update Citations, parameter notebook

Author: till-m

README.md

@@ -185,3 +185,16 @@ For constrained optimization:
     year={2014}
 }
 ```
+
+For optimization over non-float parameters:
+```
+@article{garrido2020dealing,
+  title={Dealing with categorical and integer-valued variables in bayesian optimization with gaussian processes},
+  author={Garrido-Merch{\'a}n, Eduardo C and Hern{\'a}ndez-Lobato, Daniel},
+  journal={Neurocomputing},
+  volume={380},
+  pages={20--35},
+  year={2020},
+  publisher={Elsevier}
+}
+```

docsrc/index.rst

@@ -199,6 +199,20 @@ For constrained optimization:
        year={2014}
    }
 
+For optimization over non-float parameters:
+
+::
+
+   @article{garrido2020dealing,
+       title={Dealing with categorical and integer-valued variables in bayesian optimization with gaussian processes},
+       author={Garrido-Merch{\'a}n, Eduardo C and Hern{\'a}ndez-Lobato, Daniel},
+       journal={Neurocomputing},
+       volume={380},
+       pages={20--35},
+       year={2020},
+       publisher={Elsevier}
+   }
+
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