clean up a few broken data viz and cassandra links

mattmakai · mattmakai · commit 6814e9af947c · 2019-07-15T16:23:30.000-04:00
diff --git a/content/pages/03-data/13-apache-cassandra.markdown b/content/pages/03-data/13-apache-cassandra.markdown
@@ -128,13 +128,6 @@ resulting tools as open source projects.
   to understand based on your workload and decide upon *before* you build 
   out your whole data architecture!
 
-* [Cassandra - the tale of a lonely Node](https://www.hugopicado.com/2017/05/14/cassandra-the-tale-of-a-lonely-node.html) 
-  and
-  [Cassandra - the fellowship of The Ring](https://www.hugopicado.com/2017/05/16/cassandra-the-fellowship-of-the-ring.html)
-  are good technical posts on the data structures within Cassandra's
-  architecture along with some of the problems that can pop up when
-  working with your data.
-
 * [Analyzing Cassandra Performance with Flame Graphs](http://thelastpickle.com/blog/2018/01/16/cassandra-flame-graphs.html)
   and
   [Garbage Collection Tuning for Apache Cassandra](http://thelastpickle.com/blog/2018/04/11/gc-tuning.html)
diff --git a/content/pages/03-data/18-data-visualization.markdown b/content/pages/03-data/18-data-visualization.markdown
@@ -141,11 +141,6 @@ visualization and gave me ideas for what to build.
   people worked with paper to build their visuals add fantastic context to
   the story.
 
-* [One Chart, Twelve Charting Libraries](https://lisacharlotterost.github.io/2016/05/17/one-chart-code/)
-  compares how charting libraries such as [D3.js](/d3-js.html),
-  [Matplotlib](/matplotlib.html), [Bokeh](/bokeh.html) and Seaborn 
-  compare to each other with default plotting values.
-
 * [dataviz.tools](http://dataviz.tools/) has a nice list of categorized
   tools for working with data and visualizing it.
 
diff --git a/theme/templates/pdf-book.html b/theme/templates/pdf-book.html
@@ -15,7 +15,7 @@
   {% endfor %}
   <p style="page-break-after:always;"></p>
 
-  <h1>Table of Contents</h1>
+  <h1 id="table-of-contents">Table of Contents</h1>
   {% include "book-toc.html" %}
 
   {% for page in pages|sort(attribute='sortorder') %}
