Text and Data Mining valid from 2019-09-09
Received: 7 June 2019
Accepted: 15 August 2019
First Online: 9 September 2019
Ethics approval and consent to participate
: This research received ethical approval and consent. And it didn’t require the approval of an ethics committee.
: All infants’ information contained in this manuscript has been published with the consent of their parents.
: The authors declare that they have no competing interests.