Cyclic tetrapeptides via the ring contraction strategy: chemical techniques useful for their identification

Horton, D.A., Bourne, G.T., Coughlan, J., Kaiser, S.M., Jacobs, C,M., Jones, A., Ruhmann, A., Turner, J.Y., Smythe, M.L., Organic & Biomolecular Chemistry (2008), Vol 6, Issue 8, 1386-1395.