texmath-0.7: tests/writers/mfrac-03.tex
\frac{A}{B + \frac{C}{D + \frac{E}{F}}} = \frac{\overset{\phantom{0}}{A}}{B + \frac{C}{D + \frac{E}{\underset{\phantom{0}}{F}}}}
\frac{A}{B + \frac{C}{D + \frac{E}{F}}} = \frac{\overset{\phantom{0}}{A}}{B + \frac{C}{D + \frac{E}{\underset{\phantom{0}}{F}}}}