tweak

README.md

@@ -217,6 +217,9 @@ E.g., on Terence's box, it add `/Users/parrt/anaconda3/lib/python3.6/site-packag
 * Stef van den Elzen's [Interactive Construction, Analysis and
 Visualization of Decision Trees](http://alexandria.tue.nl/extra1/afstversl/wsk-i/elzen2011.pdf)
 * Some similar feature-space visualizations in [Towards an effective cooperation of the user and the computer for classification, SIGKDD 2000](https://github.com/EE2dev/publications/blob/master/cooperativeClassification.pdf)
+* [Beautiful Decisions: Inside BigML’s Decision Trees](https://blog.bigml.com/2012/01/23/beautiful-decisions-inside-bigmls-decision-trees/)
+* "SunBurst" approach to tree visualization: [An evaluation of space-filling information visualizations
+for depicting hierarchical structures](https://www.cc.gatech.edu/~john.stasko/papers/ijhcs00.pdf)
 
 ## Authors