Serial publications with distinctive titles, containing a mix of articles, editorials, reviews, columns, short stories, or other short works written by more than one contributor, issued in softcover more than once, generally at regular stated intervals of less than a year, without prior decision as to when the final issue will appear. Although each issue is complete in itself, its relationship to preceding issues is indicated by enumeration, usually issue number and volume number printed on the front cover. At Pacific Northwest Railroad Archive, typically on railroad topics, with emphasis on the Pacific Northwest.

Serial publications with distinctive titles, containing a mix of articles, editorials, reviews, columns, short stories, or other short works written by more than one contributor, issued in softcover more than once, generally at regular stated intervals of less than a year, without prior decision as to when the final issue will appear. Although each issue is complete in itself, its relationship to preceding issues is indicated by enumeration, usually issue number and volume number printed on the front cover. At Pacific Northwest Railroad Archive, typically on railroad topics, with emphasis on the Pacific Northwest.