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. It is specified as a reprint of Appendix A of CIFS: Monograph Series 610, Merrill, P.W. 1956, Lines of the Chemical Elements in Astronomical Spectra (Washington D.C.: Carnegie Institute of Washington). However, a US Copyright Office Search shows no result under the book's title (i.e., Moore & Merrill 1968's title) nor under the names of authors Charlotte E. Moore (1887--1961) and Paul W. Merrill (1887--1961).
Image link: NED: Partial Grotrian Diagrams of Astrophysical Interest (see also NASA/IPAC Extragalactic Database (NED)).