Here is one source,http://books.google.com.hk/books?id=aIO ... q=&f=false
try IV Retracing an ancient debate, p. 96. Then flip down to page 110, ref. to de la Vallee Poussin's article, parts of which are appended at the end.
And this is only sourcing the Pali sources. If one really wants to delve into it, there are more. Gombrich botches his read of the Chinese version of Susima sutta.
There is also coverage in Schmithausen, L. (1981): “On Some Aspects of Descriptions or Theories of ‘Liberating Insight’ and ‘Enlightenment’ in Early Buddhism”, pp. 199-250, in Studein zum Jainismus und Buddhismus, Bruhn, K & Wezler, A, eds, Franz Steiner Verlag: Wiesbaden.