@conference {cedergren80convergence,
	title = {Convergence and Minimal Mutation Criteria for Evaluating Early Events in TRNA Evolution},
	booktitle = {Proceedings of the National Academy of Sciences (U.S.A.)},
	volume = {77},
	year = {1980},
	author = {Cedergren, R.J. and Larue, B. and Sankoff, D. and Guy Lapalme and Grosjean, H.}
}
