↑ “Kai Siegbahn, Swedish Physicist, Dies at 89.”. New York Times. 7 tháng 8 năm 2007. Kai Siegbahn, a Swedish physicist whose work in developing a novel technique using electrons to test the composition and purity of materials won a Nobel Prize in 1981, died on July 20. He was 89 and had been visiting his summer home in Ängelholm, in southern Sweden. ||ngày truy cập= cần |url= (trợ giúp)
