INTERFACIAL CHEMISTRY ASPECTS OF DE-INKING FLOTATION OF MIXED OFFICE PAPER, J. Drelich, J. Pletka, P. Boyd, E. Raber, D. Herron, E. Luhta, H. Walqui, N. Tervo, S. Boston, J. Wieland, J. Morgan, and N. Sabo (01-9)