Ok, I found that section in the PLN book, at 10.6.2.1 on page 211.

However, saying 
```
(NotLink
    (ConceptNode "CanadianPeople"))
```
would mean "things that are not canadian people" whereas the sentence says
```
Non Canadian People
```
which I interpret as meaning something different: "all things that are people but are not canadian people", equivalent to another concept "all people that are not canadian" (the set difference of "people" and "canadian people").