1. Superconductivity at 93 K in a new mixed-phase Y-Ba-Cu-O compound system at ambient pressure
2. R. J. Cava, B. Batlogg, R. B. van Dover, D. W. Murphy, S. Sunshine, T. Siegrist, J. P. Remeika, E. A. Rietman, S. Zuhurah and G. P. Espinosa, preprint.
3. J. F. Smith and D. M. Parkin, private communication.
4. R. D. Taylor, private communication.