Talks of ‘Abdu’l-Baha – which ones form “a part of Bahá'í Scripture”?

The original of "Some Answered Questions" in Persian is preserved in the Holy Land; its text was read in full and corrected by ‘Abdu'l-Bahá Himself. Unfortunately, Abdu'l-Bahá did not read and authenticate all transcripts of His other talks, some of which have been translated into various languages and published. For many of His addresses included in "The Promulgation of Universal Peace" and "Paris Talks", for example, no original authenticated text has yet been found. However, the Guardian allowed such compilations to continue to be used by the friends. In the future each talk will have to be identified and those which are unauthenticated will have to be clearly distinguished from those which form a part of Bahá'í Scripture. This does not mean that the unauthenticated talks will have to cease to be used -- merely that the degree of authenticity of every document will have to be known and understood. (From a letter dated 23 March 1987 written on behalf of the Universal House of Justice included in a Memorandum from the Research Department of the Universal House of Justice, dated 28 March 1996 attached to a letter written on behalf of the Universal House of Justice to an individual believer, dated 22 October, 1996)

For "Abdu'l-Bahá in London", no original transcripts exist, and the following letter was written on behalf of Shoghi Effendi in this regard:

Regarding "’Abdu'l-Bahá in London": Nothing can be considered scripture for which we do not have an original text. A verbatim record in Persian of His talks would of course be more reliable than one in English, because He was not always accurately interpreted. However such a book is of value, and certainly has its place in our Literature. (From a letter dated 24 October 1947 written on behalf of the Universal House of Justice to the National Spiritual Assembly of the British Isles, published in "Unfolding Destiny: The Messages from the Guardian of the Bahá'í Faith to the Bahá'í Community of the British Isles"; London: Bahá'í Publishing Trust, 1981)
(Memorandum from the Research Department of the Universal House of Justice, dated 28 March 1996 attached to a letter written on behalf of the Universal House of Justice to an individual believer, dated 22 October, 1996)