Article PDF
Rights and permissions
About this article
Cite this article
Mr Michael Graham. Nature 236, 248 (1972). https://doi.org/10.1038/236248a0
Issue Date:
DOI: https://doi.org/10.1038/236248a0
Nature volume 236, page 248 (1972)
Mr Michael Graham. Nature 236, 248 (1972). https://doi.org/10.1038/236248a0
Issue Date:
DOI: https://doi.org/10.1038/236248a0