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Submitted on: 19 July 1998.
Revised on: 07 October 1998.
Accepted on: 25 October 1998.
___________________Archives of Disease in Childhood-Fetal and Neonatal Edition
Submitted on: 21 May 2010.
Revised on: 18 September 2010.
Accepted on: 30 September 2010.
___________________Archives of Disease in Childhood-Fetal and Neonatal Edition
Submitted on: 26 January 2016.
Revised on: 05 May 2016.
Accepted on: 17 June 2016.
___________________Archives of Disease in Childhood-Fetal and Neonatal Edition
Submitted on: 21 September 2012.
Revised on: 13 November 2012.
Accepted on: 14 December 2012.
___________________Archives of Disease in Childhood-Fetal and Neonatal Edition
Submitted on: 28 January 2008.
Revised on: 27 February 2008.
Accepted on: 20 April 2008.
___________________Archives of Disease in Childhood-Fetal and Neonatal Edition
Submitted on: 19 November 2011.
Revised on: 23 January 2012.
Accepted on: 15 February 2012.
___________________Archives of Disease in Childhood-Fetal and Neonatal Edition
Submitted on: 19 November 1999.
Revised on: 04 February 2000.
Accepted on: 17 March 2000.
___________________Archives of Disease in Childhood-Fetal and Neonatal Edition
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