2 literature references for Isopterygium subaptychopsis Brotherus in Corbière, 1912:

Author: Crosby, M. R. and others - INSUFFICIENT
Year: 1999
Title: INSUFFICIENTLY known because not REVISED since its pre-1963 publication; that is to say we have no more information about the species than Index Muscorum; merely relisted without additional specimens in a checklist since 1963; may have been treated in
Source: Checklist Mosses
Author: Brotherus in Corbière
Year: 1912
Title:
Source: Bull. Mus. Natl. Hist. Nat.