I.C.S. REFERENCE LIBRARY; A SERIES OF TEXTBOOKS PREPARED FOR THE STUDENTS OF THE INTERNATIONAL CORRESPONDENCE SCHOOLS AND CONTAINING IN PERMANENT FORM THE INSTRUCTION PAPERS, EXAMINATION QUESTIONS, AND KEYS USED IN THEIR VARIOUS COURSES; SINGLE-ENTRY BOOK-KEEPING, ELEMENTARY DOUBLE-ENTRY BOOK-KEEPING, WHOLESALE MERCHANTS' ACCOUNTS, FOREIGN MERCHANTS' ACCOUNTS, COMPANIES ACCOUNTS, BUSINESS SYSTEMS.