A MANUAL FOR TEACHERS INCLUDING DEFINITIONS, PRINCIPLES, AND RULES DIFFICULT PROBLEMS BY JOHN H. WALSH ASSOCIATE SUPERINTENDENT OF PUBLIC INSTRUCTION BOSTON, U.S.A. D. C. HEATH & CO., PUBLISHERS |
A MANUAL FOR TEACHERS INCLUDING DEFINITIONS, PRINCIPLES, AND RULES DIFFICULT PROBLEMS BY JOHN H. WALSH ASSOCIATE SUPERINTENDENT OF PUBLIC INSTRUCTION BOSTON, U.S.A. D. C. HEATH & CO., PUBLISHERS |