1           1987-04-18.23  
 2           1989-08-25.15  Dahlgren et al. (1998) 
 3           1989-08-26.20  Dahlgren et al. (1998) 
 4           1989-08-27.22  Dahlgren et al. (1998) 
 5           1989-08-28.20  Dahlgren et al. (1998) 
 6           1989-08-29.13  Dahlgren et al. (1998) 
 7           1991-10-30.11  Dahlgren et al. (1998) 
 8           1991-10-31.11  Dahlgren et al. (1998) 
 9           1991-11-01.06  Dahlgren et al. (1998) 
10           1991-11-02.10  Dahlgren et al. (1998) 
11           1991-11-03.06  Dahlgren et al. (1998) 
12           1994-04-06.89  Dahlgren et al. (1998) 
13           1994-04-08.89  Dahlgren et al. (1998) 
14           1994-04-09.95  Dahlgren et al. (1998) 
15           1994-04-11.91  Dahlgren et al. (1998) 
16  1998-09-13--2012-02-05  Lowell