me solve this discrete. Photo solutions would be so much appreciated. Ref- Heath, T., Euclid: The Thirteen Books of the Elements, Volume 2, Second Edition, Dover Publications, New York, 1956. 2) Knuth, D., The Art of Computer Programming, Volume 1, Addison-Wesley, Reading, Mass., 1968. [3] Pengelley, D., Richman, F., Did Euclid need the Euclidean algorithm to prove unique factorization?, American Mathematical Monthly 113 (2006), 196-205. http://www.math.nmsu.edu/~davidp/euclid.pdf.