1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H
1991ApJ...377..192H