Declassified document AECD (series). 2283. Preliminary studies of toxicity of thorium [articles]; by H. Ackermnn, R. P. Allen, G. Bonner, W. L. Downs, H. C. Hodge, E. A. Maynard, W. P. Neuman, J. K. Scott, A. Sparks, H. E. Stokinger.