Diston, pp. 129-138.

Plane.

Barnard, pp. 74-80.

Selden, pp. 11-26, 165-175.

Sickels pp. 72-75, 116.

Wheeler, pp. 445-458.

Hammacher, pp. 377-400.

Smith, R. H., pp. 16-31.

Larsson, p. 19.

Goss, pp. 41-52.