This is the 1999 Code. The 1985 Code, which was in force back them, had the same sentence, except that it lacked the words "or writing". (Conclude what you want...)
This was obviously written with an intent to be (very) unfriendly--in fact I have always found it stunning that this text had been published. Walter Bock (in his own words) wanted "the International Commission on Zoological Nomenclature to adopt formally the presented list of avian family-group names as the official base-line dated 1 January 1994 for all future nomenclatural decisions relating to avian family-group names". Obviously Storrs Olson did not want to see this happen at any cost...
Anyway, the main thing I wanted to communicate here, is that it is (really) preferable to cross-check what is written in this work systematically, and not to accept anything blindly. Without wanting to use Olson's language, the work includes decisions that were deliberately taken at variance with the Code (eg., Bock wrote:
...and he went on, deliberately ignoring this requirement and accepting names from that period knowing full well that they lack a description; this subsequently created confusing situations such as that described on the first page of Appendix 2 of the H&M4 preview), and it includes mistakes (some of which are indeed described by Olson, and among which Olphe-Galliard's name may apparently be counted).
This being said, this work has no equivalent so far, and it is certainly extremely useful--as long as you handle it with care.