diff --git a/src/ifcparse/IfcSpfHeader.cpp b/src/ifcparse/IfcSpfHeader.cpp
index 4a4e5316c8..14cfe8e91a 100644
--- a/src/ifcparse/IfcSpfHeader.cpp
+++ b/src/ifcparse/IfcSpfHeader.cpp
@@ -26,11 +26,12 @@ static const char * const HEADER			= "HEADER";
 static const char * const FILE_DESCRIPTION	= "FILE_DESCRIPTION";
 static const char * const FILE_NAME			= "FILE_NAME";
 static const char * const FILE_SCHEMA		= "FILE_SCHEMA";
-static const char * const FILE_POPULATION	= "FILE_POPULATION";
-static const char * const SECTION_LANGUAGE	= "SECTION_LANGUAGE";
-static const char * const SECTION_CONTEXT	= "SECTION_CONTEXT";
 static const char * const ENDSEC			= "ENDSEC";
 static const char * const DATA				= "DATA";
+// The following header entities are not normally encountered in IFC files and are not parsed.
+// static const char * const FILE_POPULATION   = "FILE_POPULATION";
+// static const char * const SECTION_LANGUAGE  = "SECTION_LANGUAGE";
+// static const char * const SECTION_CONTEXT   = "SECTION_CONTEXT";
 
 using namespace IfcParse;
 
@@ -61,6 +62,16 @@ void IfcSpfHeader::read() {
 	readTerminal(ISO_10303_21, TRAILING_SEMICOLON);
 	readTerminal(HEADER, TRAILING_SEMICOLON);
 
+	// | The header section of every exchange structure shall contain one 
+	// | instance of each of the following entities: file_description, file_name, 
+	// | and file_schema, and they shall appear in that order. Instances of 
+	// | file_population, section_language and section_context may appear after 
+	// | file_schema. If instances of user-defined header section entities are 
+	// | present, they shall appear after the header section entity instances 
+	// | defined in this section.
+	// 
+	// ISO 10303-21 Second edition 2002-01-15 p. 16
+
 	readTerminal(FILE_DESCRIPTION, TRAILING_PAREN);
 	delete _file_description;
 	_file_description = new FileDescription(_lexer);
@@ -96,7 +107,6 @@ void IfcSpfHeader::write(std::ostream& os) const {
 	os << DATA << ";" << "\n";
 }
 
-
 const FileDescription& IfcSpfHeader::file_description() const {
 	if (_file_description) {
 		return *_file_description; 
diff --git a/src/ifcparse/IfcSpfHeader.h b/src/ifcparse/IfcSpfHeader.h
index 2f3e96e9f4..98725f50c7 100644
--- a/src/ifcparse/IfcSpfHeader.h
+++ b/src/ifcparse/IfcSpfHeader.h
@@ -50,13 +50,13 @@ protected:
 	}
 
 	void setArgument(unsigned int i, const std::string& s) {
-		IfcWrite::IfcWriteArgument* argument = new IfcWrite::IfcWriteArgument(this);
+		IfcWrite::IfcWriteArgument* argument = new IfcWrite::IfcWriteArgument;
 		argument->set(s);
 		_list->set(i, argument);
 	}
 
 	void setArgument(unsigned int i, const std::vector<std::string>& s) {
-		IfcWrite::IfcWriteArgument* argument = new IfcWrite::IfcWriteArgument(this);
+		IfcWrite::IfcWriteArgument* argument = new IfcWrite::IfcWriteArgument;
 		argument->set(s);
 		_list->set(i, argument);
 	}
diff --git a/src/ifcparse/IfcWrite.cpp b/src/ifcparse/IfcWrite.cpp
index d2dddad630..43fd76c8ae 100644
--- a/src/ifcparse/IfcWrite.cpp
+++ b/src/ifcparse/IfcWrite.cpp
@@ -134,7 +134,7 @@ void IfcWritableEntity::arg_writable(int i, bool b) {
 
 template <typename T> void IfcWritableEntity::_setArgument(int i, const T& t) {
 	if ( arg_writable(i) ) delete args[i];
-	IfcWriteArgument* arg = new IfcWriteArgument(this);
+	IfcWriteArgument* arg = new IfcWriteArgument;
 	args[i] = arg;
 	arg->set(t);
 	arg_writable(i,true);
diff --git a/src/ifcparse/IfcWrite.h b/src/ifcparse/IfcWrite.h
index 2007f4d6cc..04a7c6d89f 100644
--- a/src/ifcparse/IfcWrite.h
+++ b/src/ifcparse/IfcWrite.h
@@ -55,7 +55,6 @@ namespace IfcWrite {
 		};		
 		class Derived {};
 	private:
-		IfcAbstractEntity* entity;
 		boost::variant<
 			// A null argument, it will always serialize to $
 			boost::none_t,
@@ -108,7 +107,6 @@ namespace IfcWrite {
 			IfcEntityListList::ptr
 		> container;
 	public:
-		IfcWriteArgument(IfcAbstractEntity* e) : entity(e) {}
 		template <typename T> const T& as() const {
 			if (const T* val = boost::get<T>(&container)) {
 				return *val;