003700a00a22001330004500245004300000100001900043100002200062260004300084260000900127300001200136440005900148760001100207015001800218  aRefraction and its Components in Twins  aSorsby, Arnold  aSheridan, Michael  bLondon:Her Majesty's Stationery Office  c1962  a1-43pgs  aMedical Research Council Special Report Series No. 303  bH Room  aList No. 1987