http://i.imgur.com/Oj4kg.png
http://i.imgur.com/CckjP.jpg
from, respectively,
Madgi Ragheb, UIUC https://netfiles.uiuc.edu/mragheb/www/NPRE%20457%20CSE%20462...
NRC http://www.nrc.gov/reading-rm/basic-ref/teachers/03.pdf
