[1] Cohen Jr., E.A. (2013) On the Decomposition of a Bounded Close Interval of the Real Line into Closed Sets. Advances in Pure Mathematics, 3, 405-408.
http://dx.doi.org/10.4236/apm.2013.34058
[2] Natanson, I.P. (1961) Theory of Functions of a Real Variable. Volume 1, Frederick Ungar Publishing Co., Inc., New York, 54.
[3] Rose, N.J. (2010) Hilbert-Type Space-Filling Curves.
http://www4.ncsu.edu/~njrose/pdfFiles/HilbertCurve.pdf
[4] Hall, D.W. and Spencer II, G.L. (1955) Elementary Topology. John Wiley and Sons, Inc., New York, 72, 78.
[5] Bourbaki, N. (1971) General Topology. Springer-Verlag, 24.