The Singapore Statement on Research Integrity (Section 6), to which the HKU Policy on Research Integrity makes reference, states the following:

Researchers should take responsibility for their contributions to all publications, funding applications, reports and other representations of their research. Lists of authors should include all those and only those who meet applicable authorship criteria. 

Researchers should acknowledge in publications the names and roles of those who made significant contributions to the research, including writers, funders, sponsors, and others, but do not meet authorship criteria.