John WoodJ.W.CampbellJohn WoodJ.W., Analog Science Fiction/science Fact, Davis Publications, 1969, s. 168 [dostęp 2023-06-28], Cytat: a highly realistic yarn about prospecting and claim – jumping inside the Earth. This could be the ultimate development of the old gimmick of the man who can walk through walls(ang.).
BrianB.AldissBrianB., HarryH.HarrisonHarryH., Hell’s Cartographers, Courier Dover Publications, 13 czerwca 2018, s. 81, ISBN 978-0-486-83140-4 [dostęp 2023-06-28](ang.).
AlgisA.BudrysAlgisA., Galaxy Magazine: Science Fiction, UPD Publishing Corporation, 1967, s. 126 [dostęp 2023-06-28], Cytat: a real landmark SF story, in the especial sense that each of them either originated or first fruited a basic technological idea in such a happy combination with story values that it is impossible to touch that idea again without having to find some totally new framework for it(ang.).
