Phys Rev B Condens Matter
March 1992
Phys Rev B Condens Matter
February 1992
Phys Rev B Condens Matter
February 1992
Phys Rev B Condens Matter
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Phys Rev B Condens Matter
October 1991
Phys Rev B Condens Matter
January 1991
Phys Rev B Condens Matter
January 1991
Phys Rev B Condens Matter
October 1990
Phys Rev B Condens Matter
July 1990
Phys Rev B Condens Matter
March 1990
Phys Rev B Condens Matter
February 1990
Phys Rev B Condens Matter
November 1989
Phys Rev B Condens Matter
November 1989