@article{Shanker:1939:OEP,
author = {Shanker, Hari},
title = {On the expansion of the parabolic cylinder function
in a series of the product of two parabolic cylinder functions},
journal = {J. Indian Math. Soc. (N. S.)},
volume = {3},
year = {1939},
pages = {226–230},
zblno = {0022.13501}}