K. Kwitter, E. Lehman, B. Balick, and R. Henry. (2012)cite arxiv:1202.4933
Comment: 46 pages, including 12 figures and 8 tables, submitted to the
Astrophysical Journal.
M. Bridson, and K. Vogtmann. (2010)cite arxiv:1007.2598
Comment: Incorrect Lemma (2.5) replaced by new Proposition 2.5. Typos
corrected, references updated.