External References
http://www.sdbonline.org/fly/neural/period.htm
http://flybase.org/reports/FBgn0003068.html
Read more about this topic: Period (gene)
Famous quotes containing the word external:
“It can be fairly argued that the highest priority for mankind is to save itself from extinction. However, it can also be argued that a society that neglects its children and robs them of their human potential can extinguish itself without an external enemy.”
—Selma Fraiberg (20th century)