ISBN is not the only way to verify a reference For instance references I used in Ban Bori article are recent scans by Google Scanning project of most notable Hungarian historian researchers of Hungary s royalty Sorry they didn t have ISBN system invented 16th 19th century You have just demonstrated how rude you are by reverting my edits of Ban Bori article while the editing was still in progress You also did it again as in here for the House of Berislavi without bothering to discuss it in Talk If you are the owner of Wikimedia Foundation please let me know so that I don t bother any more