Table 1.

Published relevant papers identified in the PubMed data base, according to year and location of study

Publication date	Total (n)	Selected papers (n)	Place of study (n)
10 years ago	86	15	Austria (n = 4), Canada (n = 3), Colombia (n = 1), Singapore (n = 2), US (n = 4), worldwide (n = 1)
5 years ago	44	10	Austria (n = 2), Canada (n = 2), Singapore (n = 2), US (n = 3), worldwide (n = 1)
3 years ago	27	5	Austria (n = 1), Singapore (n = 1), US (n = 2), worldwide (n = 1)
2 years ago	17	2	Austria (n = 1), Singapore (n = 1) US (n = 2)
Last year	8	1	US (n = 2)