Letters from Doug Higley, Daura Calhelha, Jan Peterson, D. L. Grant, Pamela Holland, Ardith Ekstrom, James M. Osterburg, David Corcoran; Bobby Stanco, and John Walkin.
Original indexer only listed this being signed by Al Williamson, but Roy Krenkel's initials "RGK" are right above Williamson signature. Most likely both artists penciled AND inked this story.
Retitled "The Phantom Flag" in the Unknown Worlds reprint.
Information about the reprint from FlashJay through the GCD-Main email list.