3.1 Characterization of the literature
A total of 165 studies were identified by the search strategy after
removing duplicates. The title and abstract screening excluded 85
studies. The full text was obtained for 76 peer-reviewed papers, 13
conference proceeding from SIL, which included AASV (n = 6), IPVS (n =
6) and Leman (n = 1), one from AAVLD, one from ACVP conference
proceedings. No proceedings were extracted from CRWAD. Three studies
(Ding et al., 1983; Geyer et al., 1994; Lan et al., 2012) were excluded
because did not have an available full text. From 76 studies, 48 were
excluded in the second stage after full-text screening including 42
nonrelevant papers, four review papers, and one non-English paper.
Finally, 29 studies were identified as relevant to the review (Fig 1).