Text and Data Mining valid from 2018-03-24
Received: 20 April 2017
Accepted: 22 March 2018
First Online: 24 March 2018
Compliance with Ethical Standards
: All authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were 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. Institutional Review Board at the corresponding author’s institution had reviewed and approved the use of the restricted NLAAS dataset, a secondary data obtained from the ICPSR at the University of Michigan, as an exempted status.
: For this type of study, formal consent is not required.