Allouche, J.-P. 和 Shallit, J. "Repetition in Words." §1.6 in Automatic Sequences: Theory, Applications, Generalizations. Cambridge, England: Cambridge University Press, pp. 14-16, 2003.Finch, S. R. "Pattern-Free Word Constants." §5.17 in Mathematical Constants. Cambridge, England: Cambridge University Press, pp. 367-371, 2003.Sloane, N. J. A. Sequences A028445, A051042, and A051043 in "The On-Line Encyclopedia of Integer Sequences."
, 2, ... 的二元立方自由詞的數量為 2, 4, 6, 10, 16, 24, 36, 56, 80, 118, ... (OEIS A028445)。二元立方自由詞滿足
, 2, ... 的三元立方自由詞的數量為 3, 9, 24, 66, 180, 486, 1314, ... (OEIS A051042)。長度為 
, 2, ... 的四元立方自由詞的數量為 4, 16, 60, 228, 864, 3264, 12336, ... (OEIS A051043)。