1 files changed, 4 insertions, 0 deletions
diff --git a/_zshrc b/_zshrc
index d2dd537..1a54197 100644
--- a/_zshrc
+++ b/_zshrc
@@ -11,6 +11,10 @@
 ## [2] Zsh Configuration from the Ground Up
 ##     http://zanshin.net/2013/02/02/zsh-configuration-from-the-ground-up/
 ##
+## References:
+## [1] The Unix Shell's Humble if
+##     https://robots.thoughtbot.com/the-unix-shells-humble-if
+##
 ## Aaron LI
 ## Created: 2014-05-31
 ## Updated: 2016-01-30