General information about Philippa Pearce:
Wikipedia entry
Penguin Books page for Philippa Pearce
Oxford University Press page for Philippa Pearce
PP included in the Times' list of the 50 greatest postwar writers
Obituaries:
Guardian obituary by Stephanie Nettell
Independent obituary by Nicholas Tucker
Telegraph obituary
Other links:
Homerton College
"The Writer's View of Childhood" by Philippa Pearce from a 1962 The Horn Book article