  This note is a correction to a paper of Cortez, Peskin, Stockie & Varela
[SIAM J. Appl. Math., 65(2):494-520, 2004], who studied the stability of a
parametrically-forced, circular, elastic fiber immersed in an incompressible
fluid in 2D, and showed the existence of parametric resonance. The results were
represented as plots that separate parameter space into regions where the
solution is either stable or unstable. We uncovered two errors in the paper:
the first was in the derivation of the eigenvalue problem, and the second was
in the code to used to calculate the stability contours.
