Silva Suárez, Manuel (2019). "Presentación: Trazas y reflejos, perspectivas en la historia de la técnica" [Introduction: Traces and reflections, perspectives on the history of technology] (PDF). Técnica e ingeniería en España IX. Trazas y reflejos culturales externos (1898-1973) [Technology and engineering in Spain IX. Traces and external cultural reflections (1898-1973)] (in Spanish). Zaragoza, Spain: Institución "Fernando el Católico". pp. 15–16. ISBN978-84-7820-814-2. Retrieved 28 January 2024.
"Entsorgung von Kleinmengen ins Abwasser" [Disposal of small quantities into waste water] (in German). Frieie Universität Berlin. 9 January 2014. Archived from the original on 29 May 2022. Retrieved 28 November 2021.
Dayal, Priyanka (29 October 2008). "Marlboro chemist sues over seizure". Telegram. Worcester Telegram & Gazette Corp. Archived from the original on 28 September 2021. Retrieved 28 September 2021.
"Entsorgung von Kleinmengen ins Abwasser" [Disposal of small quantities into waste water] (in German). Frieie Universität Berlin. 9 January 2014. Archived from the original on 29 May 2022. Retrieved 28 November 2021.
Dayal, Priyanka (29 October 2008). "Marlboro chemist sues over seizure". Telegram. Worcester Telegram & Gazette Corp. Archived from the original on 28 September 2021. Retrieved 28 September 2021.