RT Journal Article SR Electronic T1 Spending an additional 40 min outdoors each day reduces the incidence of myopia among primary school children in China JF Archives of disease in childhood - Education & practice edition JO Arch Dis Child Educ Pract Ed FD BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health SP 219 OP 219 DO 10.1136/archdischild-2016-311102 VO 101 IS 4 YR 2016 UL http://ep.bmj.com/content/101/4/219.abstract AB