@article{JOLT_2017_27_3_a7,
     author = {M. Libine},
     title = {The {Two-Loop} {Ladder} {Diagram} and {Representations} of {U(2,2)}},
     journal = {Journal of Lie Theory},
     pages = {771--800},
     year = {2017},
     volume = {27},
     number = {3},
     doi = {10.5802/jolt.969},
     zbl = {1383.22011},
     url = {https://jolt.centre-mersenne.org/articles/10.5802/jolt.969/}
}