@article{10_4153_CJM_1986_072_6,
     author = {Apostol, Constantin and Fialkow, Lawrence},
     title = {Structural {Properties} of {Elementary} {Operators}},
     journal = {Canadian journal of mathematics},
     pages = {1485--1524},
     year = {1986},
     volume = {38},
     number = {6},
     doi = {10.4153/CJM-1986-072-6},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1986-072-6/}
}