> which started at the Norwegian Computing Center in the Spring of 1961
The date is wrong; only Simula 67 qualifies as an "object-oriented" language (the term was not used then though). The development of Simula 67 started in 1966. The author probably means the predecessor language, which did not have the properties associated with object orientation (moreover, it was a simulation language, whereas Simula 67 was designed as a general purpose programming language).
> Smalltalk-72 ... was clearly inspired by Simula, and took from Simula the ideas of classes, objects, object references, and inheritance
Smalltalk-72 had no inheritance. Kay was aware of it but didn't like the idea. Only Ingalls added it to his Smalltalk-76 implementation.
Not the only inaccuracies as it seems.