1. A Proof for the Queuing Formula:L= λW
2. Marchwinski , C . 2009. Following four steps to a lean material-handling system leads to a leap in performance [online]. Knowledge Center. Available at: www.lean.org [Accessed 30 June 2011]
3. Monden , Y . 1998.The Toyota production system. 3rd edn. Norcross, Georgia: Engineering and Management Press (a division of the Institute of Industrial Engineers)