Lol, yes, I know that poem/rythm.
Heimskringla is the same as Nordiska Kungasagor, just another name for it.
Heimskringla is mentioned in Jules Vernes "Journey to the Center of the Earth".
Funny fact: there is a newspaper in Icelandic language in Winnipeg in Manitoba called Heimskringla. :-)
For those who wants to check this out:
http://www.wisdomlib.org/scandinavia/book/heimskringla/index.html