Fix broken link: PODC queues

data_structures/README.md

@@ -1,7 +1,7 @@
 # Data Structures
 
 * [Dynamic Hash Tables](http://www.csd.uoc.gr/~hy460/pdf/Dynamic%20Hash%20Tables.pdf)
-* [Simple, Fast, and Practical Non-Blocking and Blocking Concurrent Queue Algorithms](http://www.research.ibm.com/people/m/michael/podc-1996.pdf)
+* [Simple, Fast, and Practical Non-Blocking and Blocking Concurrent Queue Algorithms](https://www.cs.rochester.edu/u/scott/papers/1996_PODC_queues.pdf)
 * [RRB-Trees: Efficient Immutable Vectors](http://infoscience.epfl.ch/record/169879/files/RMTrees.pdf)
 * [Cuckoo Hashing](http://www.it-c.dk/people/pagh/papers/cuckoo-jour.pdf)
 * [Fenwick Tree](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.14.8917&rep=rep1&type=pdf)