1. Andrews DG, Bonner KD, Butterworth AW, Calvert HR, Dagang BRH, Dimond KJ, Eckenroth LG, Erickson JM, Gilbertson BA, Gompertz NR, Igbinosun OJ (2015) Defining a successful commercial asteroid mining program. Acta Astronautica 108:106–118
2. Astrobotics (2019) Peregrine lunar lander payload user’s guide. Retrieved from
https://www.astrobotic.com/payload-user-guide
3. Calla, Pablo, Dan Fries, And Chris Welch (2019). Asteroid mining with small spacecraft and its economic feasibility, Preprint submitted to Acta Astronautica-Under Review
4. Cowley, Alison and Margery Ryan (2019). The PGM report. London: Johnson Matthey, PLC. (
http://www.platinum.matthey.com/documents/new-item/pgm%20market%20reports/pgm_market_report_may_19.pdf
)
5. Dahl, Carol A. (2020a). Critical minerals: what are they and what makes them critical? Division of economics and business working paper series. WP2020–04, Colorado School of Mines, Golden, CO, June
https://econbus.mines.edu/wp-content/uploads/sites/29/2020/04/wp202004.pdf