Krishnamurthy & Suri 2009, pp. 596–610. Krishnamurthy, Ananth; Suri, Rajan (2009). "Planning and implementing POLCA: a card-based control system for high variety or custom engineered products". Production Planning & Control. 20 (7): 596–610. doi:10.1080/09537280903034297. S2CID109046909.
Krishnamurthy & Suri 2009, pp. 596–610. Krishnamurthy, Ananth; Suri, Rajan (2009). "Planning and implementing POLCA: a card-based control system for high variety or custom engineered products". Production Planning & Control. 20 (7): 596–610. doi:10.1080/09537280903034297. S2CID109046909.