diff --git a/Go2ErrorValuesFeedback.md b/Go2ErrorValuesFeedback.md
index 95c502d9..a29ef1a7 100644
--- a/Go2ErrorValuesFeedback.md
+++ b/Go2ErrorValuesFeedback.md
@@ -31,6 +31,7 @@ As the amount of feedback grows, please feel free to organize this page by speci
  - Paul Meyer, “[errors.New?]( - _Your Name_, “[_Title_](#URL)”, August 2018
  - Vojtech Vitek "[adopt Cause and Wrap from github.com/pkg/errors](https://golang.org/issue/25675)", May 2018
  - Andrew Wilkins "[Programmatic Frame inspection](https://gist.github.com/axw/247b6f69d2da016bb21a5eb1be44e611)", January 2019
+- _Carl Johnson_, "[_ As() and Is() are useful for optional interfaces beyond error_](https://gist.github.com/carlmjohnson/d06cd8d10e0aef65f565a55cc57cd986), Feb. 2019
  - _Your Name_, “[_Title_](#URL)”, _month year_
  - etc.