APA
National Stone Association N., . (1993). Stone sand seminar at Knoxville, TN, March 28-30, 1993. Proceedings. Washington DC: National Stone Association, NSA.
Chicago
National Stone Association NSA, . 1993. Stone sand seminar at Knoxville, TN, March 28-30, 1993. Proceedings. Washington DC: National Stone Association, NSA.
Harvard
National Stone Association N., . (1993). Stone sand seminar at Knoxville, TN, March 28-30, 1993. Proceedings. Washington DC: National Stone Association, NSA.
MLA
National Stone Association NSA, . Stone sand seminar at Knoxville, TN, March 28-30, 1993. Proceedings. Washington DC: National Stone Association, NSA. 1993.