Beckman, ea 1990
Beckman, J.S., Beckman, K.M., Chen, J., Marshall, P.A., and Freeman, P.A. (1990) Proc. Natl. Acad. Sci. USA, 87, 1620-1624.
Beckman, J.S., Beckman, K.M., Chen, J., Marshall, P.A., and Freeman, P.A. (1990) Proc. Natl. Acad. Sci. USA, 87, 1620-1624.
