1977 With A. H. Knoll. Archean microfossils showing cell division from the Swaziland system of South Africa. Science 198:396-398.
1978 With S. Francis and L. Margulis. On the experimental silicification of microorganisms. II. On the time of appearance of eukaryotic organisms in the fossil record. Precambrian Res. 6:65-100.
1979 With B. H. Tiffney. Flora of the Brandon lignite. IV. Illiciaceae. Am. J. Bot. 66:321-329.
1980 With L. Margulis, D. Ashendorf, S. Banerjee, D. Chase, S. Francis, S. Giovannoni, and J. F. Stolz. The microbial community in the layered sediments at Laguna Figueroa, Baja California, Mexico: Does it have Precambrian analogues? Precambrian Res. 11:93-123.
1982 With C. Lenk, P. K. Strother, and C. A. Kaye. Precambrian age of the Boston Basin: New evidence from microfossils. Science 216:619-620.