Received: 17 October 2019
Accepted: 3 June 2020
First Online: 18 June 2020
Ethics approval and consent to participate
: None sought as this was a systematic review of published studies.
: Not applicable as the paper does not contain any individual person’s data.
: The authors declare that they have no conflict of interest. The authors would like to highlight that they included a paper they wrote in this review.