Clicking on a button on the left navigation bar will either open a page or extend the menu. Clicking on the FOREWORD button for example, displays the message page by the OPEC Secretary General, while clicking on the button GENERAL NOTES, will extend the menu and displays related submenus.
	Some of the submenus are again divided into several topics, e.g. DEFINITIONS, which will display several related topics. Click on one of them to view the page .
	Click on any parent button or one of the main buttons to close the submenu and/or topics.