@article{AV_1933__4_2_a1,
     author = {Lenz, V.},
     title = {On some joint-life annuities},
     journal = {Aktu\'arsk\'e v\v{e}dy},
     pages = {97--102},
     publisher = {mathdoc},
     volume = {04},
     number = {2},
     year = {1933},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AV_1933__4_2_a1/}
}