Correction
OCT 01, 1978
DOI: 10.1063/1.3043354
August, page 36—In Bernard Cooper’s article on coal research, the sentence beginning on the 21st line from the bottom of the middle column should read: “However, such effects fall off strongly with increasing angle, and for angles from about 70° up to normal incidence, the deformation–fatigue mechanism offers basic understanding.”
© 1978. American Institute of Physics
