diff --git a/README.md b/README.md
index 9a3eec5..8178250 100755
--- a/README.md
+++ b/README.md
@@ -123,7 +123,8 @@ Inspired by [Awesome Deep Learning](https://github.com/ChristosChristofidis/awes
 
 ### Software-specific
 
-1.  _[Analyzing Social Networks](https://sites.google.com/site/analyzingsocialnetworks/)_ (using UCINET), by Stephen P. Borgatti, Martin G. Everett and Jeffrey C. Johnson (2013).
+1.  _[Algorithmic Graph Theory and Sage](https://code.google.com/archive/p/graphbook/)_, by David Joyner, Minh Van Nguyen, and David Phillips - Full book online (2013).
+-   _[Analyzing Social Networks](https://sites.google.com/site/analyzingsocialnetworks/)_ (using UCINET), by Stephen P. Borgatti, Martin G. Everett and Jeffrey C. Johnson (2013).
 -   _[A User's Guide to Network Analysis in R](https://www.springer.com/us/book/9783319238821)_, by Douglas A. Luke (2015).
 -   _[Data Science and Complex Networks: Real Case Studies with Python](https://global.oup.com/academic/product/data-science-and-complex-networks-9780199639601)_, by Guido Caldarelli and Alessandro Chessa (2016).
 -   _[Exploratory Social Network Analysis with Pajek](http://www.cambridge.org/us/academic/subjects/sociology/research-methods-sociology-and-criminology/exploratory-social-network-analysis-pajek-2nd-edition)_, by Wouter de Nooy, Andrej Mrvar and Vladimir Batagelj (2011; also [in Japanese](http://www.tdupress.jp/books/isbn978-4-501-54710-3.html) and [in Chinese](http://product.dangdang.com/22927985.html)).
@@ -474,6 +475,7 @@ Inspired by [Awesome Deep Learning](https://github.com/ChristosChristofidis/awes
 -   [Polinode](https://www.polinode.com/) - Web-based platform to both analyze network data as well as collect network data via relationship-based surveys.
 -   [PUCK - Program for the Use and Computation of Kinship data](http://www.kintip.net/content/view/55/21/) - Cross-platform Java program for genealogical network analysis.
 -   [Radatools](http://deim.urv.cat/~sergio.gomez/radatools.php) - Set of tools intended for the analysis of complex networks, built on top of [Radalib](http://deim.urv.cat/~sergio.gomez/radalib.php), a library written in Ada.
+-   [SageMath](http://www.sagemath.org/) - Free open-source mathematics software with extensive [graph capabilities](http://doc.sagemath.org/html/en/reference/graphs/index.html).
 -   [Segrada](http://segrada.org/) - Cross-platform tool to build and visualize semantic graph databases.
 -   [Siena](http://www.stats.ox.ac.uk/~snijders/siena/) - Simulation Investigation for Empirical Network Analysis. Formerly a Windows program, now developed as the RSiena R package.
 -   [SocNetV - Social Network Visualizer](http://socnetv.sourceforge.net/) - Cross-platform program that includes a [simple Web crawler](http://socnetv.sourceforge.net/news/?post=socnetv-v16-released-with-a-working-web-crawler) to construct hyperlink networks.