Mepụta ụdị okwu a dị mgbagwoju anya Ọ bụ Svein Rosseland chepụtara ya, ma rụọ ya na Knut Strøm Gundersen (1909 - 1983) nke ụlọ ọrụ na-emepụta ngwá ọrụ azụmahịa nke Norway bụ Gundersen & Løken.
N'ezie, ụdị okwu dị mgbagwoju anya nke ahịrịokwu ahụ bụ "Ọ bụ Svein Rosseland mere ya, nke Gundersen & Løken, onye na-emepụta ngwá ahịa na Norway, wuru, ma tinye ya na ala nke mbụ nke Institute for Theoretic Astrophysics na Mahadum Oslo. "