A galley proof is the initial proof stage when text is set to the correct line width but not made up into pages. On a galley proof the text appears as a single, uninterrupted column and the figures and tables do not appear in their final positions. The gap analysis technique is sometimes used by drug companies to identify publications that might support the marketing of their products. A ghost author is somebody who qualifies for authorship but is not included in a publication's author list. The term 'ghost writers' is sometimes applied to a professional medical writer who has not been involved with a study but who helps develop a publication – in particular, by preparing the first draft. Green Open Access denotes journals that allow authors to self-archive their work, but that don't give immediate free access to readers via the journal website. Journals that have adopted the contributorship system may ask that one contributor guarantees the project's integrity.