@techreport{Diwan:1986,
	key = "Diwan 1986",
	author = "A. A. Diwan",
	title = "A new combinatorial complexity measure for languages",
	institution = "Computer Science Group, Tata Institute, Bombay",
	year = 1986}

@article{Althofer:1990,
	key = "Alth{\"o}fer 1990",
	author = "I. Alth{\"o}fer",
	title = "Tight lower bounds for the length of word chains",
	journal = IPL,
	volume = 34,
	year = 1990,
	pages = "275-276",
	comment = "checked"}

@article{RothP:1989,
	key = "P. Roth 1989",
	author = "P. Roth",
	title = "A note on word chains and regular languages",
	journal = IPL,
	volume = 30,
	year = 1989,
	pages = "15-18",
	comment = "checked"}

@article{Bousquet-Melou:1992,
	key = "{Bousquet-M\'elou} 1992",
	author = "M. {Bousquet-M\'elou}",
	title = "The number of minimal word chains computing the
{Thue-Morse} word",
	journal = IPL,
	volume = 44,
	year = 1992,
	pages = "57-64",
	comment = "checked"}

@article{Arnold&Brlek:1989,
	key = "Arnold and Brlek 1989",
	author = "A. Arnold and S. Brlek",
	title = "Optimal word chains for the {Thue-Morse} word",
	journal = IC,
	volume = 83,
	year = 1989,
	pages = "140-151"}

@article{Berstel&Brlek:1987,
	key = "Berstel and Brlek 1987",
	author = "J. Berstel and S. Brlek",
	title = "On the length of word chains",
	journal = IPL,
	volume = 26,
	year = "1987/88",
	pages = "23-28",
	comment = "checked"}

@article{Merekin:1998,
	key = "Merekin 1998",
	author = "Yu. V. Merekin",
	title = "Upper bounds for the complexity of sequences generated
by symmetric Boolean functions",
	journal = "Diskretn. Anal. Issled. Oper. Ser. 1",
	volume = 5,
	number = 3,
	year = 1998,
	pages = "38-43,96",
	note = "In Russian.  English translation in
{\it Disc. Appl. Math.} {\bf 114} (2001), 227--231"}