diff --git a/distributed_systems/README.md b/distributed_systems/README.md
index ae1de66..b07968a 100644
--- a/distributed_systems/README.md
+++ b/distributed_systems/README.md
@@ -17,6 +17,8 @@
 
 * [Chord: A Scalable Peer-to-peer Lookup Service for Internet Applications](http://pdos.csail.mit.edu/papers/chord:sigcomm01/chord_sigcomm.pdf)
 
+* [Introduction to a System for Distributed Databases SDD-1](http://www.few.vu.nl/~kgr700/sdd1.pdf)
+
 * [Kafka: a Distributed Messaging System for Log Processing](http://research.microsoft.com/en-us/um/people/srikanth/netdb11/netdb11papers/netdb11-final12.pdf)
 
 * [Large-scale cluster management at Google with Borg](http://static.googleusercontent.com/media/research.google.com/en/us/pubs/archive/43438.pdf)