@article{Langford:1958,
	key = "Langford 1958",
	author = "C. D. Langford",
	title = "Problem",
	journal = MG,
	volume = 42,
	year = 1958,
	pages = "228"}

@article{Priday:1959,
	key = "Priday 1959",
	author = "C. J. Priday",
	title = "On {Langford's} problem {(I)}",
	journal = MG,
	volume = 43,
	year = 1959,
	pages = "250-253"}

@article{Davies:1959,
	key = "Davies 1959",
	author = "R. O. Davies",
	title = "On {Langford's} problem {(II)}",
	journal = MG,
	volume = 43,
	year = 1959,
	pages = "253-255"}

@article{Marcus&Paun:1989,
	key = "Marcus and {P\u aun} 1989",
	author = "S. Marcus and G. {P\u aun}",
	title = "Langford strings, formal languages, and contextual ambiguity",
	journal = IJCM,
	volume = 26,
	year = 1989,
	pages = "179-191"}

@incollection{Paun:1992,
	key = "{P\u aun} 1992",
	author = "G. {\noopsort{Paun}}{P\u aun}",
	title = "Anti-{Langford} sequences",
	booktitle = "Words, Languages and Combinatorics",
	editor = "M. Ito",
	year = 1992,
	publisher = WSP,
	pages = "410-421"}