00309nas a2200121   4500000000100000000000100001008004100002100001600043245003100059856007800090300001200168490000700180       1960                            d1 aErik Åhman00aHelge Backlund in memoriam  uhttps://paleoarchive.com/literature/Ahman1960-HelgeBacklundInMemoriam.pdf  aI–XIX0 v38