J Mol Evol. 1989 Nov;29(5):373-80 doi:10.1007/bf02602907

Osawa S, Ohama T, Jukes TH, Watanabe K, Yokoyama S.

Evolution of the mitochondrial genetic code. II. Reassignment of codon AUA from isoleucine to methionine.

Codon capture hypothesis. Cites the Crick preprint.