Convergence-Evoked Nystagmus
Neurol 40:161-162, Oliva,A.&Rosenberg,M.L., 1990
Primary Position Upbeating Nystagmus:A Variety of Central Positional Nystagmus
Brain 106:949-964, Fisher,A.,et al, 1983
Upbeat Nystagmus
JAMA 225:312, Daroff,R.B.,et al, 1973