Calculations for Magnetism in SQUIDs at Millikelvin Temperatures
  Here we present details of a calculation that allows us to extract a surface density of unpaired spins from flux vs. temperature experiments performed on field-cooled dc Superconducting QUantum Interference Devices (dc SQUIDs). 
S. Sendelbach, D. Hover, A. Kittel, M. M\"uck, John M. Martinis, and   R. McDermott