Pas plus compliqué que cela

From Author Wars - https://authorwars.com/books/pas-plus-complique-que-cela-1991099.html

Overview:

Title: Pas plus compliqué que cela
Author: Zenna Henderson
Year: 1976
Type: Short Fiction

Editions/Publications:

Unknown. Les enfants de la nuit (Unknown, Zenna Henderson, Marabout, 377+[7] pages, Paperback, Collection)