1. J. D. Mill, R. R. O’Neil, S. Price, G. J. Romick, et al., Spacecr. Rockets 31, 900 (1994).
2. R. Simon, J. M. Jackson, J. M. Rathborne, and E. T. Chambers, Astrophys. J. 639, 227 (2006).
3. N. Peretto and G. A. Fuller, Astron. Astrophys. 505, 405 (2009).
4. C. Battersby, J. Bally, J. M. Jackson, A. Ginsburg, Y. L. Shirley, W. Schlingman, and J. Glenn, Astrophys. J. 721, 222 (2010).
5. L. Blitz, in Protostars and Planets III, Ed. by E. H. Levy and J. I. Lunine (Univ. Arizona Press, Tucson, AZ, 1993).