diff --git a/GCM-for-SM4.md b/GCM-for-SM4.md
index 8aa06db..7660812 100644
--- a/GCM-for-SM4.md
+++ b/GCM-for-SM4.md
@@ -89,3 +89,4 @@ gcmSm4Enc, gcmSm4Dec, 已完成AMD64架构下非AVX(2)版本及AVX(2)版本，
         zip1 s2.2d, RTMP3.2d, RTMP1.2d;     \ // s2 = s0.S2, s1.S2, s2.S2, s3.S2
         zip2 s3.2d, RTMP3.2d, RTMP1.2d;	      // s3 = s0.S3, s1.S3, s2.S3, s3.S3
 ```
+[Intel Carry-Less Multiplication Instruction and its Usage for Computing the GCM Mode](https://www.intel.com/content/dam/develop/external/us/en/documents/clmul-wp-rev-2-02-2014-04-20.pdf)
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