title: On the chemical constitution of cometary nuclei.
mesh_terms: D055580:Astronomical Phenomena; D001256:Astronomy; D002248:Carbon Monoxide; D003903:Deuterium; D005557:Formaldehyde; D008697:Methane; D014867:Water
chemical_list: D014867:Water; D005557:Formaldehyde; D002248:Carbon Monoxide; D003903:Deuterium; D008697:Methane