A few endnotes include an “a” suffix.
Many references to endnotes that reference another book are followed by a pair of square brackets containing the page number in that other book.
The book also has four footnotes that originally were at the bottoms of pages, but have been moved here to follow the paragraphs that reference them. They use simple “abcd” references.
Three endnotes are unreferenced ([XII-14], [XIII-2] and [XIII-6]); several are referenced more than once.
The index was not systematically checked for proper alphabetization or correct page references.