"Stamina has two uses: casting spells (1 stamina per spell level), and ... "
I can't find the level of each spell, it's an errata? Or the numbers of the list are the levels so Wizardry Warding Spell is a 20 level spell? I don't think so but..
I look at the Knave spells but there are no levels for the spells. They are level-less.