ISOCAM contours taken at 4.5, 6.75 and 15 microns of the starburst galaxy NGC3998. The image in the lower right hand corner is a digitized POSS red plate.

These images were presented in;
"ISO observations of hot dust in the nucleus of the S0 galaxy NGC 3998", Knapp G.R. et al.

that was published in the ISO dedicated issue of Astronomy and Astrophysics Letters.