diff --git a/pkn.html b/pkn.html
index 4b45957..e5e69e5 100644
--- a/pkn.html
+++ b/pkn.html
@@ -248,7 +248,7 @@ <h2>Data Types</h2>
   
   <p>PKN documents use the following restricted set of data types. See <a href="#grammar"></a> for a formal definition of their serialization.</p>
 
-    <p>A <dfn>number</dfn> represents a double-precision 64-bit format value as specified in the IEEE Standard for Binary Floating-Point Arithmeticis [[IEEE-754-2019]]. It is serialized in base 10 using decimal digits, following the same grammar as <a data-cite="RFC8259#section-6">numbers in JSON</a> [[RFC8259]].</p>
+    <p>A <dfn>number</dfn> represents a double-precision 64-bit format value as specified in the IEEE Standard for Binary Floating-Point Arithmetic [[IEEE-754-2019]]. It is serialized in base 10 using decimal digits, following the same grammar as <a data-cite="RFC8259#section-6">numbers in JSON</a> [[RFC8259]].</p>
     
     <p>A <dfn>name</dfn> is a string that can include letters, digits, colon, period, hyphen, underscore and slash characters, and that cannot be interpreted as a [=number=].</p>