KOAKUTSU , TOMOAKI, NAOKI MOROZUMI, TAKESHI HOSHIKAWA, SHINJI OGAWA, YUSHIN ISHII, and EIJI ITOI. 2011. “Bilateral Spondylolysis of Inferior Articular Processes of the Fourth Lumbar Vertebra: A Case Report”. Upsala Journal of Medical Sciences 117 (1):72–77. https://doi.org/10.3109/03009734.2011.629750.