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Huelsen, Alexander; Fischer, Jesse; Hegarty, Justin; Ashcroft, Anna; Frampton, Christopher Ma; Barclay, Murray L. (2016-12-02). "The scratch test for identifying the lower liver edge is at least as accurate as percussion and is significantly more effective for young trainees-a randomised comparative trial". The New Zealand Medical Journal. 129 (1446): 53–63. ISSN1175-8716. PMID27906919.