Morse Theory by John Milnor
= Morse Theory by John Milnor
{c}
{tag=Work by John Milnor}
{title2=1963}
Princeton University Press book; inspected title page dates the edition 1963. Institutional scan: https://pagine.dm.unipi.it/~a019210/Milnor_Morse%20theory.pdf
Lemma 2.2 gives the exact smooth quadratic normal form and its completion-of-squares proof. Corollary 2.3 gives isolation of nondegenerate critical points and contrasts degenerate examples such as x cubed.