
 Marc Sabatella's Jazz Improvisation Primer: Basic Theory 
  Expanding by half steps, the remaining intervals are the minor third, major third, perfect fourth, tritone, perfect fifth, minor sixth, major sixth, minor seventh, major seventh, and finally, the octave. 
  For example, the tritone interval from C to Gb, which is actually the same as the interval from C to F#, is called a diminished fifth, because the interval from C to G is a perfect fifth. 
  The motion of roots in this progression is upwards by perfect fourth, or, equivalently, downward by perfect fifth. 
 www.outsideshore.com /primer/primer/msprimer41.html (2093 words) 
