Kruglyak, Natan, Lech Maligranda, y Lars-Erik Persson. «Structure of the Hardy Operator Related to Laguerre Polynomials and the Euler Differential Equation». Revista Matemática Complutense 19, no. 2 (julio 13, 2006): 467–476. https://doi.org/10.5209/rev_REMA.2006.v19.n2.16613.