References:

Gustafson, R. J. (2003). A View of Future Human Colonies on Mars. AIP Conference Proceedings. doi:10.1063/1.1541426

M. (2016, June 30). Martian DEM[TIFF]. Goddard Space Flight Center

Martian Water Concentration. (2006). USGS. ftp://pdsimage2.wr.usgs.gov/pub/pigpen/mars/grs/

Musk.E (2016). Mars_Presentation. Retrieved from
http://www.spacex.com/sites/spacex/files/mars_presentation.pdf

Rice, Eric E. “Optimized ISRU Propellants for Propulsion and Power Needs for Future Mars Colonization.” AIP Conference Proceedings (2003): n. pag. Web.

SpaceX, (2016, September 27). SpaceX Interplanetary Transport System
Retrieved from https://www.youtube.com/watch?v=0qo78R_yYFA&t=174s