add SIAM CSE21

Author: michelp

README.md

@@ -114,6 +114,14 @@ downloaded from
 
 # Workshops and conferences featuring the GraphBLAS (reverse chronological)
 
+* [SIAM CSE'21 GraphBLAS Minisymposium Session 1](https://meetings.siam.org/sess/dsp_programsess.cfm?SESSIONCODE=70090)
+
+* [SIAM CSE'21 GraphBLAS Minisymposium Session 2](https://meetings.siam.org/sess/dsp_programsess.cfm?SESSIONCODE=70091)
+
+* [SIAM CSE'21 GraphBLAS Tutorial Session 1](https://meetings.siam.org/sess/dsp_programsess.cfm?SESSIONCODE=69893)
+
+* [SIAM CSE'21 GraphBLAS Tutorial Session 2](https://meetings.siam.org/sess/dsp_programsess.cfm?SESSIONCODE=70367)
+
 * [Graphs, Architectures, Programming, and Learning (GrAPL) @IPDPS](http://hpc.pnl.gov/grapl/)
 
 * [High Performance Extreme Computing (HPEC)](http://www.ieee-hpec.org/)