Using the ToC
You can quickly find the article you want on the Text page:

Enter an article number (here, 477), and click ToC to scroll to the correct line in the Table of Contents; clicking Article will jump straight to the webpage for article 477.
To look up an article by edition, select the edition and volume, and type the page number; then tabbing will populate the next box with the article number:

indicates that page 153 of the second volume of the Haroun edition is article 140.