study  authors             year   x1i    t1i    x2i    t2i
1      "Bong et al."       2003     7   1344     11   1988
2      "Ciresi et al."     1996     8   1600      8   1461
3      "Hanna et al."      2004     3  12012     14  10962
4      "Harter et al."     2002     6   1536     10   1503
5      "Jaeger et al."     2001     1    370      1    483
6      "Jaeger et al."     2005     1    729      8    913
7      "Logghe et al."     1997    17   6760     15   6840
8      "Ostendorf et al."  2005     3   1107      7   1015
9      "Pemberton et al."  1996     2    320      3    440
