Vaniman, D.; Pettit, D.; Heiken, G. (1992). "Uses of lunar sulfur". Lunar Bases and Space Activities of the 21st Century. SAO/NASA Astrophysics Data System (ADS): 429. Bibcode:1992lbsa.conf..429V. Archived from the original on 30 August 2023. Retrieved 30 August 2023.
Vaniman, D.; Pettit, D.; Heiken, G. (1992). "Uses of lunar sulfur". Lunar Bases and Space Activities of the 21st Century. SAO/NASA Astrophysics Data System (ADS): 429. Bibcode:1992lbsa.conf..429V. Archived from the original on 30 August 2023. Retrieved 30 August 2023.
Vaniman, D.; Pettit, D.; Heiken, G. (1992). "Uses of lunar sulfur". Lunar Bases and Space Activities of the 21st Century. SAO/NASA Astrophysics Data System (ADS): 429. Bibcode:1992lbsa.conf..429V. Archived from the original on 30 August 2023. Retrieved 30 August 2023.