You can find a few articles about Gwen Harwood's pseudonym-esque type poetry in which literary critics actually cite examples and interpret what each of her different pseudonyms might mean. Likewise, they note how she uses the pseudonym to catalog or organize character traits.

Cassandra L. Atherton has published a book defining this nature called Flashing Eyes and Floating Hair: A Reading of Gwen Harwood's Pseudonymous Poetry. Being an Australian author, I think you would easily find this in a library there. However, if you are anywhere else, you may be looking at a purchase.

Her work "In the Park" particularly defines the division of self and has received especially from her friends and colleague she knows the distinction as an author bent on the subpersonality.

Finding any greater critique than the links below may require username and password access to a local library that contains articles, journals and books online in their subscription databases.