@article {Gatesy1993_188,
	title = {Alignment ambiguous nucleotide sites and the exclusion of systematic data},
	journal = {Molecular Phylogenetics and Evolution},
	volume = {2},
	number = {2},
	year = {1993},
	pages = {152{\textendash}157},
	author = {Gatesy, J. and DeSalle, R. and Wheeler, W.}
}
