Add links to dataset websites

datasets/README.md

@@ -2,3 +2,8 @@
 
 This directory contains simple scripts to retrieve and unpack datasets used in
 the examples.
+
+## Dataset websites
+
+- [DTD](https://www.robots.ox.ac.uk/~vgg/data/dtd/)
+- [CIFAR-10](https://www.cs.toronto.edu/~kriz/cifar.html)