* LaChapelle, Edward R.; Stillman, R. M. (1962). The chemical modification of depth hoar, part II - "Project C, progress report no. 4.". Colorado St. University Library, Basement: Alta Avalanche Study Center. pp. 1-5 | * LaChapelle, Edward R.; Stillman, R. M. (1962). The chemical modification of depth hoar, part II - "Project C, progress report no. 4.". Colorado St. University Library, Basement: Alta Avalanche Study Center. pp. 1-5 |