remove references sections, empty in pdf build (removal OK in html)

Author: trevorcampbell

source/classification1.md

@@ -1974,7 +1974,6 @@ found in {numref}`Chapter %s <move-to-your-own-machine>`. This will ensure that
 and guidance that the worksheets provide will function as intended.
 
 +++
-## References
 
 ```{bibliography}
 :filter: docname in docnames

source/classification2.md

@@ -2205,8 +2205,6 @@ and guidance that the worksheets provide will function as intended.
   text, it requires a bit more mathematical background than we require.
 
 
-## References
-
 +++
 
 ```{bibliography}

source/clustering.md

@@ -1063,8 +1063,6 @@ and guidance that the worksheets provide will function as intended.
   learning, it covers *principal components analysis (PCA)*, which is a very
   popular technique for reducing the number of predictors in a data set.
 
-## References
-
 +++
 
 ```{bibliography}

source/inference.md

@@ -1363,10 +1363,6 @@ and guidance that the worksheets provide will function as intended.
 
 +++
 
-## References
-
-+++
-
 ```{bibliography}
 :filter: docname in docnames
 ```

source/intro.md

@@ -1233,8 +1233,6 @@ make sure to follow the instructions for computer setup
 found in {numref}`Chapter %s <move-to-your-own-machine>`. This will ensure that the automated feedback
 and guidance that the worksheets provide will function as intended.
 
-## References
-
 +++
 
 ```{bibliography}

source/jupyter.md

@@ -515,3 +515,10 @@ underscore (`_`).
   formatting, two good places to start are CommonMark's [Markdown
   cheatsheet](https://commonmark.org/help/) and [Markdown
   tutorial](https://commonmark.org/help/tutorial/).
+
++++
+
+```{bibliography}
+:filter: docname in docnames
+```
+

source/reading.md

@@ -1626,8 +1626,6 @@ and guidance that the worksheets provide will function as intended.
     - [extracting the data for apartment listings on Craigslist](https://www.youtube.com/embed/YdIWI6K64zo), and
     - [extracting Canadian city names and populations from Wikipedia](https://www.youtube.com/embed/O9HKbdhqYzk).
 
-## References
-
 +++
 
 ```{bibliography}

source/references.bib

@@ -336,7 +336,7 @@ @inproceedings{kluyver2016jupyter
   title={Jupyter Notebooks: a publishing format for reproducible computational workflows},
   author={Kluyver, Thomas and Ragan-Kelley, Benjamin and P{\'e}rez, Fernando and Granger, Brian and Bussonnier, Matthias and Frederic, Jonathan and Kelley, Kyle and Hamrick, Jessica and Grout, Jason and Corlay, Sylvain and Ivanov, Paul and Avila, Dami{\'a}n and Abdalla, Safia and Willing, Carol and {Jupyter Development Team}},
   year={2016},
-  booktitle = {Positioning and Power in Academic Publishing: Players, Agents and Agendas: Proceedings of the $20^{\text{th}}$ international conference on electronic publishing},
+  booktitle = {Positioning and Power in Academic Publishing: Players, Agents and Agendas: Proceedings of the 20th international conference on electronic publishing},
   publisher = {IOS Press},
   volume = {87},
   address = {Amsterdam}
@@ -508,7 +508,7 @@ @article{requests
 @article{rhoophiuchi,
   title = {Rho Ophiuchi cloud complex},
   author = {{NASA} and {ESA} and {CSA} and {STScI} and {K. Pontoppidan (STScI)} and {A. Pagan (STScI)}},
-  year = {2023},
+  year = {Accessed Online: 2023},
   journal={URL: https://esawebb.org/images/weic2316a/}}
 
 

source/regression1.md

@@ -1206,10 +1206,6 @@ and guidance that the worksheets provide will function as intended.
 
 +++
 
-## References
-
-+++
-
 ```{bibliography}
 :filter: docname in docnames
 ```

source/regression2.md

@@ -1395,8 +1395,6 @@ and guidance that the worksheets provide will function as intended.
   covered earlier are indeed more flexible but become very slow when given lots
   of data.
 
-## References
-
 +++
 
 ```{bibliography}