Hohmann transfer - Math bibliographies - in Harvard style

In-text: (Curtis, 2005)

Your Bibliography: Curtis, H., 2005. Orbital mechanics for engineering students. Oxford: Elsevier Butterworth-Heinemann.

In-text: (Manley, 2014)

Your Bibliography: Manley, S., 2014. Orbital Mechanics On Paper - Part 1 - Addendum. [video] Available at: <https://www.youtube.com/watch?v=000zDI2nmq8> [Accessed 29 January 2015].

In-text: (Verger et al., 2003)

Your Bibliography: Verger, F., Sourbès-Verger, I., Ghirardi, R., Lyle, S. and Reilly, P., 2003. The Cambridge encyclopedia of space. Cambridge, UK: Cambridge University Press.

In-text: (Widnall and Peraire, 2015)

Your Bibliography: Widnall, S. and Peraire, J., 2015. Lecture L17 - Orbit Transfers and Interplanetary Trajectories.

In-text: (Kerbin - Kerbal Space Program Wiki, 2015)

Your Bibliography: Wiki.kerbalspaceprogram.com. 2015. Kerbin - Kerbal Space Program Wiki. [online] Available at: <http://wiki.kerbalspaceprogram.com/wiki/Kerbin> [Accessed 29 January 2015].