Credit/Permission: Moore, C. E. & Merrill, P. W. 1968, Partial Grotrian Diagrams of Astrophysical Interest (Washington D.C.: Government Printing Office (GPO)) / Believed to be in the Public domain. The book was published by US Government Printing Office without copright notice. NIST (National Bureau of Standards (NBS) 1901--1988) itself has posted the book online at Moore & Merrill (1968).