diff --git a/ch04.asciidoc b/ch04.asciidoc
index c97f8c3a..4f9e4199 100644
--- a/ch04.asciidoc
+++ b/ch04.asciidoc
@@ -236,7 +236,7 @@ To visualize multiplication of a point with an integer, we will use the simpler
 
 [TIP]
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-((("secp256k1 optimized C library")))Bitcoin uses the https://github.com/bitcoin-core/secp256k1[secp256k1 optimized C library] to do the elliptic curve math. For example, to derive the public key, the function +EC_POINT_mul()+ is used.((("", startref="KAover04")))
+((("secp256k1 optimized C library")))Bitcoin uses the https://github.com/bitcoin-core/secp256k1[secp256k1 optimized C library] to do the elliptic curve math.((("", startref="KAover04")))
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 [[ecc_illustrated]]