odt_file = models.FileField(_('ODT file'), upload_to='books/odt', blank=True)
html_file = models.FileField(_('HTML file'), upload_to='books/html', blank=True)
+ parent = models.ForeignKey('self', blank=True, null=True)
+
objects = managers.ModelTaggedItemManager(Tag)
tags = managers.TagDescriptor(Tag)