An on-going project of cross-referencing reprint and preprint series distributed by observatories to the collection of the National Radio Astronomy Observatory is described. Reprints available in the library's journal collection were removed after cross-indexing and referencing was accomplished. If the reprint was not available through the journal collection, it was kept and filed in the same folder as the annotated list of reprints, organized by observatory. The work varied with each observatory's publications--simple identification of reprints being kept and being removed for those observatories that published their own annotated list of reprints was easy; for those series where no indexes existed, annotated indexes had to be created. This procedure allows the library to maintain the intent of identifying a work with a particular institution, but at the same time allows for considerable space savings and simplification of the collection by keeping a particular article in only one location in the library. (Author/MBR)