Hobbs (1977) cites the following examples from his corpus as being problematic for his tree-search algorithm:

(a) The thin, hard, black-burnished pottery, made in shapes of angular profile, which archaeologists consider as the clearest hallmark of the Lung Shan culture, developed in the east. The site from which it takes its name is in Shantung. It is traced to the north-east as far as Liao-ning province.

(b) He had the duty of performing the national sacrifices to heaven and earth: his role as source of honors and material rewards for services rendered by feudal lords and ministers is commemorated in thousands of inscriptions made by the recipients on bronze vessels which were eventually deposited in their graves.

In each case, identify the correct referent of the underlined pronoun and the one that the algorithm will identify incorrectly. Discuss any factors that come into play in determining the correct referent in each case, and what types of information might be necessary to account for them