Arch Dis Child. 2011 Nov;96(11):pp. 1008-13. http://adc.bmj.com/content/early/2011/02/01/adc.2010.191882.full
Child Care Health Dev. 2011 Jan;37(1):55-63. doi: 10.1111/j.1365-2214.2010.01111 Abstract Objectives: Accompanying guardians (usually...