E. V. Held
发表
Massimo Capaccioli,
G. M. Richter,
H. Lorenz,
1988
.
R. Brast,
E. Diolaiti,
C. Arcidiacono,
2008,
0803.3728.
Ulrich Hopp,
E. Carretta,
Richard P. Boyle,
1916,
Science.
A. Bragaglia,
V. Ripepi,
A. F. Martinez Fiorenzano,
2005
.