QLabel with HTML-style formatting docs?

[Everall]

Hello,

in the book
C++ GUI Programming with QT3 chapter 1, there is an example where some
HTML-style formatting is used on a QLabel.

QLabel *label = new QLabel("<h2><i>Hello</i> "
                               "<font color=red>Qt!</font></h2>", 0);

QLabel *label = new QLabel("<h2><i>Hello</i> "
                               "<font color=red>Qt!</font></h2>", 0);

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Can someone point me to any documentation where I can read more about it?

Thanks