Smith 2000,第20頁 The majority of ‘Abdu’l-Bahá’s writings are from the period 1892–1921, while a few have an earlier date: Secret of Divine Civilization (1875), A Traveller’s Narrative (1886) and his commentary on ‘I was a Hidden Treasure’. Smith, Peter. A Concise Encyclopedia of the Bahá'í Faith. Oxford, UK: Oneworld Publications. 2000 [2017-05-10]. ISBN 1-85168-184-1. (原始内容存档于2019-04-01).
Smith 2000,第20頁 The majority of ‘Abdu’l-Bahá’s writings are from the period 1892–1921, while a few have an earlier date: Secret of Divine Civilization (1875), A Traveller’s Narrative (1886) and his commentary on ‘I was a Hidden Treasure’. Smith, Peter. A Concise Encyclopedia of the Bahá'í Faith. Oxford, UK: Oneworld Publications. 2000 [2017-05-10]. ISBN 1-85168-184-1. (原始内容存档于2019-04-01).