diff --git a/Lib-rand.md b/Lib-rand.md
index 2df3343..792abfd 100644
--- a/Lib-rand.md
+++ b/Lib-rand.md
@@ -48,7 +48,9 @@ Generating random numbers, and sampling from random distributions.
   3. Language: R (statistical language, so much broader random number support than necessary)
     - http://stat.ethz.ch/R-manual/R-patched/library/base/html/Random.html
     - http://stat.ethz.ch/R-manual/R-patched/library/stats/html/Distributions.html
-
+  4: Library: [GSL](https://www.gnu.org/software/gsl/manual/html_node/)
+    - https://www.gnu.org/software/gsl/manual/html_node/Random-Number-Generation.html
+    - https://www.gnu.org/software/gsl/manual/html_node/Random-Number-Distributions.html
 
 ### Summary of research from other languages:
 #### Structures and functions commonly appearing