(1) 작도 가능한 수는 유리수또는 유리수의 제곱근들을 사칙연산한 수 라는 증명

Constructible Numbers    http://www.cut-the-knot.org/arithmetic/rational.shtml

(2) 정다각형의 작도

Constructible polygon  http://en.wikipedia.org/wiki/Constructible_polygon

(3) 각의 3등분

N. Schrenk and J. Bond, On the trisection of an angle and the construction of regular polygons of 7 and 9 sides

http://www.nathanschrenk.com/Survey%20Final%20Paper.pdf

(4) The Three Ancient Problems  http://www.math.tamu.edu/~dallen/masters/alg_numtheory/delian_problem.pdf

(5)  잘못된 각의 삼등분 해법 등

P. Yiu, The Regular Heptagon by Angle Trisection and Other Constructions

http://math.fau.edu/yiu/regularheptagontrisection070424.pdf

(6)  The Three Famous Problems of Antiquity
1. Dupilication of the cube 2. Trisection of an angle 3. Quadrature of the circle

http://web.mst.edu/~lmhall/5-Three%20Problems.pdf

(7)  JEFF  SUZUKI, A Brief History of Impossibility
MATHEMATICS MAGAZINE, VOL. 81, NO. 1, FEBRUARY 2008, pp. 27-38

http://mathdl.maa.org/images/upload_library/22/Allendoerfer/Suzuki.pdf