1. E. A. Wood, Acta Cryst. (to be published).
2. D. L. White (to be published).
3. A post-dated paper given at this conference by P. H. Fang and R. S. Roth on “Ferroelectric and ferrimagnetic properties of (Ba6−2xR2x) (Nb9−xFe1+x) O30” indicates that their compound is ferroelectric (thus also piezoelectric) and ferrimagnetic at the same time.