“…The cited studies were international including six from Asia (Gopinath and Chaturvedi, 1992 ; Hanzawa et al, 2013 ; Hsu and Tu, 2013 ; Chaturvedi et al, 2014 ; Kageyama et al, 2016 ; Varghese et al, 2016 ); four from the USA (Friedrich et al, 1999 ; O'Brien et al, 2006 ; Thompson, 2007 ; Copeland and Heilemann, 2008 ); three from the United Kingdom (Gibbons et al, 1984 ; Ferriter and Huband, 2003 ; Onwumere et al, 2014 ) and Australia (Vaddadi et al, 1997 , 2002 ; Loughland et al, 2009 ), and two from Sweden (Kjellin and Ostman, 2005 ; Nordström et al, 2006 ). The remaining studies had their origin in Canada (Chan, 2008 ) and Switzerland (Lauber et al, 2003 ).…”