(1) Proc. Cambridge Philos. Soc. 73 (1973), page 173

Dr E. Leibowitz has called my attention to a mistake in my paper on isotropic tensors. (1) On p. 173, if 12 is annihilated as stated and then we annihilate l13 by the same method, a new contribution to l12 appears. The correct method is to choose α so as to annihilate l21. Then a suitable rotation on the 13 plane removes l31 without re-introducing l21. The rest of the argument stands.