Army extension courses. Special text : Defensive combat and organization of the ground / prep. under the dir. of the Chief of Infantry for use … Army extension courses. Special text : Defensive combat and organization of the ground / prep. under the dir. of the Chief of Infantry for use … Army extension courses. Special text : Tank operations / prep. under the dir. of the Chief of Infantry for use with the Extension Course of … Army extension courses. Special text : Tank operations / prep. under the dir. of the Chief of Infantry for use with the Extension Course of … Army extension courses. Special text : Military discipline, courtesies and customs of the service / prep. under the dir. of the Adjutant General and the … Army extension courses. Special text : Defense against chemical warfare / prep. under the dir. of the Chief of the Chemical Warfare Service for use … Army extension courses. Special text : Medical department administration / prep. under the dir. of the Surgeon General for use with the Army Extension Courses Army extension courses. Special text : Medical department administration / prep. under the dir. of the Surgeon General for use with the Army Extension Courses Army extension courses. Special text : Dental administration / prep. under the dir. of the Surgeon General for use with the Extension Course of the … Army extension courses. Special text : Combat orders and solution of problems : medical / prep. under the dir. of the Surgeon General for use … Army extension courses. Special text : Elementary military sanitation / prep. by the Medical Field Service School under the dir. of the Surgeon General for … Army extension courses. Special text : Medical aspects of chemical warfare / prep. under the dir. of the Surgeon General and the Chief of Chemical …