4 literature references for Physcomitrium sumatranum Baumgartner & J. Fröhlich, 1953:

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: C. Müller
Year: 1900
Title:
Source: Hedwigia
Author: Baumgartner & J. Fröhlich
Year: 1953
Title:
Source: Ann. Naturhist. Mus. Wien
Author: Fife, A. J.
Year: 1982
Title:
Source: Gen. Rev. Funariaceae