Linear time distance transforms for quadtrees

Shaffer, C. A., and Q. F. Stout, "Linear time distance transforms for quadtrees", CVGIP: Image Underst., vol. 54, no. 2, Orlando, FL, USA, Academic Press, Inc., pp. 215–223, 1991.

An optimal boundary to quadtree conversion algorithm

Lattanzi, M. R., and C. A. Shaffer, "An optimal boundary to quadtree conversion algorithm", CVGIP: Image Underst., vol. 53, no. 3, Orlando, FL, USA, Academic Press, Inc., pp. 303–312, 1991.

QUILT: A Geographic Information System Based on Quadtrees

Shaffer, C. A., H. Samet, and R. C. Nelson, "QUILT: A Geographic Information System Based on Quadtrees", International Journal of Geographic Information Systems, vol. 4, no. 2, pp. 103–131, 1990.

A New Region Expansion for Quadtrees

Ang, C. - H., H. Samet, and C. A. Shaffer, "A New Region Expansion for Quadtrees", IEEE Trans. Pattern Anal. Mach. Intell., vol. 12, no. 7, Washington, DC, USA, IEEE Computer Society, pp. 682–686, 1990.

Digitizing the plane with cells of nonuniform size

Samet, H., C. A. Shaffer, and R. E. Webber, "Digitizing the plane with cells of nonuniform size", Inf. Process. Lett., vol. 24, no. 6, Amsterdam, The Netherlands, The Netherlands, Elsevier North-Holland, Inc., pp. 369–375, 1987.

Optimal quadtree construction algorithms

Shaffer, C. A., and H. Samet, "Optimal quadtree construction algorithms", Comput. Vision Graph. Image Process., vol. 37, no. 3, San Diego, CA, USA, Academic Press Professional, Inc., pp. 402–419, 1987.

Quadtree Region Representation in Cartography: Experimental Results

Samet, H., A. Rosenfeld, C. A. Shaffer, and R. E. Webber, "Quadtree Region Representation in Cartography: Experimental Results", IEEE Transactions on Systems, Man, and Cybernetics, vol. 13, no. 6, pp. 1148–1154, November/Decembe, 1983.