BOYLES, A. “The Angle of Ascent”: Process and Achievement in the Work of Robert Hayden. The Journal of Bahá’í Studies, Ottawa, Ontario, Canada, v. 4, n. 4, p. 1–28, 1991. DOI: 10.31581/jbs-4.4.434(1992). Disponível em: https://journal.bahaistudies.ca/online/article/view/434. Acesso em: 1 feb. 2023.