the 4 'elements of the effort for purity', are:
effort for purity of morality (sīla-parisuddhi-padhāniyanga),
for purity of mind (citta),
of view (ditthi),
of deliverance (vimutti).
Cf. A. IV, 194. -
Another 9 factors are enumerated in D.34, namely the 7 stages of purification (s. visuddhi) and the effort for purity of (higher) knowledge (vijjā-p.-p.) and of deliverance (vimutti-p.-p.).