References
- Von Os AFM, Van der Linden JQ. Reliability of an automatic ultrasound system in the post partum period in measuring urinary retention. Acta Obstet Gynecol Scand 2006; 85: 604–7
- Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurements. Lancet 1986; 1: 307–10