Letters in Mathematical Physics
Letters in Mathematical Physics > 1997 > 39 > 4 > 299-311
Letters in Mathematical Physics > 1997 > 41 > 2 > 161-168
Letters in Mathematical Physics > 1998 > 43 > 2 > 173-185
Letters in Mathematical Physics > 2007 > 81 > 2 > 93-105
Letters in Mathematical Physics > 2014 > 104 > 9 > 1137-1145
Letters in Mathematical Physics > 2014 > 104 > 10 > 1201-1233