There exist serious problems about all the three Late Devonion Glolal Stratotype Section and Points (GSSP) confirmed by the International Commission on Stratigraphy. Ziegler and Sand-berg (1996) proposed that these problems of the GSSP should be reconsidered.
王成源.1998.晚泥盆世全球界线层型剖面点存在的问题[J].地质论评,44(6):756-579,[DOI]. Wang Chengyuan.1998. Problems about the Late Devonian Global Stratotype Sections and Points (GSSP)[J]. Geological Review,44(6):756-579.