Locations of background continuum sources in Galactic coordinates. This plot shows only the 44 sources towards which H I OH and CO were observed. The open circles represent sources with detected H I absorption only. The squares represent sources with detected H I and OH absorption. The red triangles represent sources with CO detections, in which every detected OH component is also seen in CO. The blue dots represent sources with CO detections, in which some OH components do not have corresponding CO detections. We call these sources “partial CO detections.”