text: Most importantly, with the sequential order rules, also referred to as Nodas rules', the sequence of the intensity changes can be determined. By carefully interpreting the signs of the 2D synchronous and asynchronous cross peaks with the following rules, the sequence of spectral events during the experiment can be determined:
  #if the intensities of the bands at x and y in the dataset are changing in the same direction, the synchronous 2D cross peak at (x,y) is positive
  #if the intensities of the bands at x and y in the dataset are changing in the opposite direction, the synchronous 2D cross peak at (x,y) is negative
  #if the change at x mainly precedes the change in the band at y, the asynchronous 2D cross peak at (x,y) is positive
  #if the change at x mainly follows the change in the band at y, the asynchronous 2D cross peak at (x,y) is negative
  #if the synchronous 2D cross peak at (x,y) is negative, the interpretation of rule 3 and 4 for the asynchronous 2D peak at (x,y) has to be reversed
  :where x and y are the positions on the x-xaxis of two bands in the original data that are subject to intensity changes.
  Following the rules above. It can be derived that the changes at 10 and 30 occur simultaneously and the changes in intensity at 20 and 40 occur simultaneously as well. Because of the positive asynchronous cross-peak at (10, 20), the changes at 10 and 30 (predominantly) occur before the intensity changes at 20 and 40.
  In some cases the Noda rules cannot be so readily implied, predominately when spectral features are not caused by simple intensity variations.  This may occur when band shifts occur, or when a very erratic intensity variation is present in a given frequency range.