\input zb-basic
\input zb-ioport
\iteman{io-port 50231439}
\itemau{Gardner, R. J.}
\itemti{X-rays of polygons}
\itemso{Discrete & Computational Geometry 7, 281-293 (1992).}
\itemcc{}
\itemut{}
\itemli{doi:10.1007/BF02187842}
\end