A showing ee on level 1 diagram
B using ee symbol for process
C inconsistent data flows between level 0 and
  level 1 (e.g., level 0 shows data in and out of
  this process, level 1 doesn't)
D no interaction between subprocesses
E wellspring
F using process symbol for ee
G detached process
H impossible process name (e.g., credit card type)
I black hole
J included non-billing subprocess
K need data flows leading off to indicate
  interaction with ee
L noun as process name---hard to tell what
  activity is