@article{700174,
     title = {On the zeros of some special functions: differential equations and Nicholson-type formulas},
     booktitle = {Equadiff 6},
     series = {GDML\_Books},
     publisher = {J. E. Purkyn\v e University, Department of Mathematics},
     address = {Brno},
     year = {1986},
     pages = {[155]-160},
     mrnumber = {MR0877118},
     zbl = {0599.33013},
     url = {http://dml.mathdoc.fr/item/700174}
}

Muldoon, Martin E. On the zeros of some special functions: differential equations and Nicholson-type formulas, dans Equadiff 6, GDML_Books,  (1986), pp. [155]-160. http://gdmltest.u-ga.fr/item/700174/