diff --git a/README.md b/README.md
index d403860..46bf84a 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 PEIGEN is a tool for study S-boxes.
 
 The S-box is a type of non-linearity cryptographic component, commonly used in symmetric cryptography primitives.
-For a survey on studies of S-boxes and a formal introduction of PEIGEN, please refer to the paper [\[2\]](SoK: Peigen – a Platform for Evaluation, Implementation, and Generation of S-boxes).
+For a survey on studies of S-boxes and a formal introduction of PEIGEN, please refer to the paper [\[2\]](https://eprint.iacr.org/2019/209).
 
 ## Functionalities
 
@@ -328,7 +328,7 @@ Concrete usage are as follows.
 
 ## Final Remarks
 
-For more theoretical aspects on S-boxes and more details on PEIGEN, please refer to the paper [\[2\]](SoK: Peigen – a Platform for Evaluation, Implementation, and Generation of S-boxes).
+For more theoretical aspects on S-boxes and more details on PEIGEN, please refer to the paper [\[2\]](https://eprint.iacr.org/2019/209).
 
 Due to the storage limitation, we will not upload other results generated by PEIGEN.
 Please see https://www.dropbox.com/sh/x6y7u8gfvi0ki72/AADW7Pgy9NXFbA5_yAxNlBbga for them (> 5 GBs).
@@ -341,4 +341,4 @@ We aim to improve PEIGEN continuously. Your contributions are welcome.
 
 [1] Jérémy Jean, Thomas Peyrin, Siang Meng Sim and Jade Tourteaux.: Optimizing Implementations of Lightweight Building Blocks. https://eprint.iacr.org/2017/101.
 
-[2] Zhenzhen Bao, Jian Guo, San Ling and Yu Sasaki.: SoK: PEIGEN -- a Platform for Evaluation, Implementation, and Generation of S-boxes.
+[2] Zhenzhen Bao, Jian Guo, San Ling and Yu Sasaki.: SoK: PEIGEN -- a Platform for Evaluation, Implementation, and Generation of S-boxes. https://eprint.iacr.org/2019/209.