Lars Ove Wangensteen continues to make genealogical works available at his website Wangensteen.net. Last month I mentioned the book Den dansk-norske adelsslægt Huitfeldt (Hogenskild) ("The Danish-Norwegian noble family Huitfeldt (Hogenskild)").
Wangensteen has recently added a publication about Galtung, yet another family listed in Danmarks Adels Aarbog (Yearbook of the Danish Nobility). Galtungernes ældste historie indtil 1660 ("The Galtungs' oldest history until 1660") by O. Olafsen was published in 1910 and can be viewed here. 123 genealogical titles can now be found at Wangensteen.net, and more will be added, so check it out from time to time. For your information The Norwegian Nobility - survey of 1886 can be viewed here. H.J. Huiteldt-Kaas' article from 1886, De nulevende adelsslægter i Norge, which the survey is for the most part based on, is also included at Wangensteen.net.
Returning to the Galtung family again, as far as I know the most recent major work about this family is Galtungslekten i fortid og nutid ("The Galtung Family past and present") published by Lars F. Galtung in 1974. The work includes Johan Ellertsen Galtung's manuscript on the family from 1948, besides contributions by Henning Sollied, Lars Hamre, Olav Kolltveit, Eyvin Dahl, J.J. Jåthun, K.S. Kleppe, Asgaut Steinnes and Lars F. Galtung.
Galtungslekten i fortid og nutid was with a few changes reprinted in 1997 by Johan Ellertsen Galtung's granddaughter Elin Galtung Lihaug. The book includes 17 genealogical charts of the older and the younger Galtung families.