--- a/rdf-concepts/index.html	Thu Dec 19 10:32:12 2013 +0100
+++ b/rdf-concepts/index.html	Thu Dec 19 10:52:30 2013 +0100
@@ -203,9 +203,9 @@
     resource denoted by a literal is called its
     <a title="literal value">literal value</a>. Literals have
     <a title="datatype">datatypes</a> that define the range of possible
-    values, such as strings, numbers, and dates. A special kind of literals,
-    <a title="language-tagged string">language-tagged strings</a>, denote plain-text strings in a
-    natural language.</p>
+    values, such as strings, numbers, and dates. Special kind of literals,
+    <a title="language-tagged string">language-tagged strings</a>, denote
+    plain-text strings in a natural language.</p>
 
     <p>Asserting an <a>RDF triple</a> says that <em>some relationship,
     indicated by the <a>predicate</a>, holds between the
@@ -340,7 +340,7 @@
 
 
 <section id="change-over-time">
-    <h2>RDF and Change Over Time</h2>
+    <h2>RDF and Change over Time</h2>
 
     <p>The RDF data model is <em>atemporal</em>: <a title="RDF graph">RDF graphs</a>
       are static snapshots of information.</p>
@@ -533,7 +533,7 @@
     <p><a title="IRI">IRIs</a>, <a title="literal">literals</a>
     and <a title="blank node">blank nodes</a> are distinct and distinguishable.
     For example, <code>http://example.org/</code> as a string literal
-    is not equal to <code>http://example.org/</code> as an IRI,
+    is neither equal to <code>http://example.org/</code> as an IRI,
     nor to a blank node with the <a>blank node identifier</a>
     <code>http://example.org/</code>.</p>
 </section>
@@ -596,10 +596,10 @@
           required by IRI syntax</li>
         <li>Explicitly stated HTTP default port
           (<code>http://example.com:80/</code>);
-          <code>http://example.com/</code> is preferrable</li>
+          <code>http://example.com/</code> is preferable</li>
         <li>Completely empty path in HTTP IRIs
           (<code>http://example.com</code>);
-          <code>http://example.com/</code> is preferrable</li>
+          <code>http://example.com/</code> is preferable</li>
         <li>“<code>/./</code>” or “<code>/../</code>” in the path
           component of an IRI</li>
         <li>Lowercase hexadecimal letters within percent-encoding
@@ -721,7 +721,7 @@
     on blank node identifiers, if any, therefore also depend on
     the concrete RDF syntax or implementation.  Implementations that handle blank node
     identifiers in concrete syntaxes need to be careful not to create the
-    same blank node from multiple occurences of the same blank node identifier
+    same blank node from multiple occurrences of the same blank node identifier
     except in situations where this is supported by the syntax.</p>
 </section>
 
@@ -782,7 +782,7 @@
       <li><var>M(lit)=lit</var> for all <a title="literal">RDF literals</a> <var>lit</var> which
       are nodes of <var>G</var>.</li>
 
-      <li><var>M(uri)=uri</var> for all <a title="IRI">IRIs</a> <var>uri</var>
+      <li><var>M(iri)=iri</var> for all <a title="IRI">IRIs</a> <var>iri</var>
       which are nodes of <var>G</var>.</li>
 
       <li>The triple <var>( s, p, o )</var> is in <var>G</var> if and