1. F. Kawamoto, Y. Kishi, K. Tomita, Continued fraction expansions with even period and primary symmetric parts with extremely large end. Comm. Math. Univ. Sancti Pauli 64(2), 131–155 (2015)
2. F. Kawamoto, Y. Kishi, H. Suzuki, K. Tomita, Real quadratic fields, continued fractions, and a construction of primary symmetric parts of ELE type. Kyushu J. Math. 73(1), 165–187 (2019)
3. F. Kawamoto, K. Tomita, Continued fractions and certain real quadratic fields of minimal type. J. Math. Soc. Japan 60(3), 865–903 (2008)
4. S. Lang, Introduction to Diophantine Approximations (Addison-Wesley, Reading, MA, 1966)
5. O. Perron, Die Lehre von den Kettenbrüechen, Band I: Elementare Kettenbrüche, 3te Aufl. B. G. Teubner Verlagsgesellschaft, Stuttgart (1954)