diff --git a/fix-itchat.sh b/fix-itchat.sh
index 0fd097b..3d02fe0 100755
--- a/fix-itchat.sh
+++ b/fix-itchat.sh
@@ -2,6 +2,8 @@
 
 set -x
 
+# @see https://stackoverflow.com/questions/30003570/how-to-use-gnu-sed-on-mac-os-10-10-brew-install-default-names-no-longer-su
+# @see https://www.cnblogs.com/fnlingnzb-learner/p/10657285.html
 cmd=sed
 if [ "$(uname)" == "Darwin" ];then
   brew install gnu-sed