diff --git a/c/src/exec/posix/src/unistd.c b/c/src/exec/posix/src/unistd.c
index 5ef66ada7f..f06159f60b 100644
--- a/c/src/exec/posix/src/unistd.c
+++ b/c/src/exec/posix/src/unistd.c
@@ -9,7 +9,7 @@
 
 
 /*
- *  3.4.3 Delay Process Execution, P1003.1b-1993, p. 73
+ *  3.4.3 Delay Process Execution, P1003.1b-1993, p. 81
  */
 
 unsigned int sleep(