Jd. Romano, HYPERTIME FORMALISM FOR SPHERICALLY SYMMETRICAL BLACK-HOLES AND WORMHOLES - COMMENT, Physical review. D. Particles and fields, 55(2), 1997, pp. 1112-1113
The hypertime formalism for spherically symmetric spacetimes given by
Braham suffers from the so-called spacetime problem of time. The canon
ical variables T-+/- introduced there are not spacetime scalars, and t
hus fail to qualify as embedding variables for the theory.