Funding for this research was provided by:
Heep Hong Society, Hong Kong (5-ZH1Z)
Text and Data Mining valid from 2018-12-12
First Online: 12 December 2018
Compliance with Ethical Standards
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were carried out in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants (or their parents, for child participants) included in the study.