Cogen, William Maurice (1937) Mechanics of Landslides (Dissertation (Ph.D)), California Institute of Technology doi: 10.7907/M78R-XP91 Cogen, William Maurice (1933) A Study of the Heavy Minerals of the Modelo Formation in the Eastern Portion of the Santa Monica Mountains (Thesis (Masters)), California Institute of Technology doi: 10.7907/M8KB-ZP59 Cogen, William Maurice (1931) Geology of a Part of the Southwestern Portion of the San Gabriel Mountains (Bachelors)), California Institute of Technology doi: 10.7907/BFQX-F624