Sullivan, Ryan; Jonasdottir, Hrafnihildur; Santiago, Jessica; Nelson, Emily. "Oceanic Mapping". ASU. Archived from the original on 5 February 2021. Retrieved 30 January 2021.
Verbeek, R.D.M. (1884). Krakatau (in Dutch). Batavia, Dutch East Indies (Jakarta, Indonesia): Landsdrukkerij (Government Press). p. 164. From p. 164: "Over de gesteenten, waaruit de kegels Danan en Perboewatan bestonden, […] dat zij van de eruptie van 1680 afkomstig is."
French translation: Verbeek, R.D.M. (1886). Krakatau (in French). Batavia, Dutch East Indies (Jakarta, Indonesia): Imprimerie de l'état (Government Press). p. 171.
Donahue, Terry (5 December 2017). "The Resurrection Of Krakatau". The Indonesia Expat. Indonesiaexpat.biz. Archived from the original on 30 December 2018. Retrieved 29 December 2018.
Donahue, Terry (5 December 2017). "The Resurrection Of Krakatau". The Indonesia Expat. Indonesiaexpat.biz. Archived from the original on 30 December 2018. Retrieved 29 December 2018.
Sullivan, Ryan; Jonasdottir, Hrafnihildur; Santiago, Jessica; Nelson, Emily. "Oceanic Mapping". ASU. Archived from the original on 5 February 2021. Retrieved 30 January 2021.