Sonja is a fictional character from the Underworld series of films. This character is the daughter of the vampire elder Viktor, introduced by flashback, in Underworld. Red Sonja, the She-Devil with a Sword, is a fictional character who first appeared in Conan the Barbarian #23 (Marvel Comics).
tetralogy (plural tetralogies) 1  A set of four works of art that are connected, and that can be seen either as a single work or as four individual works. They are commonly found in literature, film, or video games. ( 2 medicine) A combination of four symptoms.
from Wikipedia, the free encyclopedia. Psychophysics is an interdisciplinary field occupying the intersection between cognitive psychology and experimental psychology and dealing with the relationship between physical stimuli and their perception.