00314nas a2200133   4500000000100000008004100001100001500042700002300057700001400080700001400094245005500108300001000163490000700173       2002                            d1 aRoberts C.1 aHenderson-Smart D.1 aAlgert C.1 aMorris J.00aTrends in twin births in NSW, Australia, 1990-1999  a213-90 v78