1. Mikhail, E., Ackermann, F.: Observations and Least Squares. Univ. Press America, New York (1976)
2. Niemeier, W.: Ausgleichungsrechnung. De Gruyter, Berlin (2002)
3. Conformal map. http://en.wikipedia.org/wiki/Conformal_map
4. Student’s t-test. http://en.wikipedia.org/wiki/T-test
5. . http://en.wikipedia.org/wiki/Graph_(mathematics)