For the purposes of discussing this feature, the determiner wan(bala), identical to the numeral 'one', is considered an indefinite article. This analysis is not unproblematic, as wan(bala) is not obligatory in indefinite contexts. Sandefur (1979: 104) considers it a marker of indefinite specificity: "There is one determiner, however, that functions somewhat like an article. Wanbala, though most often used as the number 'one', is not infrequently used in the sense of 'a certain'." Wan(bala) always precedes the head noun.
Source: Sandefur 1979: 104
Source: Galmurr and Willika 1996
Source: Brennan 1993
Source: Angelo et al. 1998