1. On the shape of the fundamental domain of the Hilbert modular group;Cohn, Harvey,1965
2. R. H. DeVore, The Lowest Points in the Fundamental Domain of the Hilbert Modular Group for 𝑄(5^{1/2}) and 𝑄(2^{1/2}), Ph.D. Dissertation, University of Arizona, Tucson, Ariz., 1964.
3. J. Nymann, Ideal Structure in Relative-quadratic Fields arising from Fixed-points of the Hilbert Modular Group, Ph.D. Dissertation, University of Arizona, Tucson, Ariz., 1965.
4. Tata Institute of Fundamental Research Lectures on Mathematics, No. 23;Siegel, Carl Ludwig,1965