Unknown, March 1939

From Author Wars - https://authorwars.com/publications/unknown-march-1939-61849.html

Overview:

Title: Unknown, March 1939
Author: uncredited
Year: 1939
Publisher: Street & Smith Publications, Inc.
Price: $0.20
Pages: 164
Binding: pulp
Type: MAGAZINE
Title Reference: Sinister Barrier (Complete Novel)
Notes: Volume I, Number 1
Cover illustration for "Sinister Barrier" (untitled in the magazine). Interior art by Cartier, Hewitt, Fisk, Mayan, Orban, Gilmore, and Isip.
Miller/Contento titles the Wellman story with an emdash instead of an ellipsis.