THE DUTCH TWINS PRIMER. Grade I.
THE ESKIMO TWINS. Grade II.
THE DUTCH TWINS. Grade III.
THE j.a.pANESE TWINS. Grade IV.
THE SWISS TWINS. Grade IV.
THE FILIPINO TWINS. Grade V.
THE IRISH TWINS. Grade V.
THE ITALIAN TWINS. Grade V.
THE MEXICAN TWINS. Grade V.
THE SCOTCH TWINS. Grade VI.
THE BELGIAN TWINS. Grade VII.
THE FRENCH TWINS. Grade VII.
Historical Series
THE CAVE TWINS. Grade IV.
THE SPARTAN TWINS. Grade V.
THE COLONIAL TWINS OF VIRGINIA. Grade VI.
THE AMERICAN TWINS OF 1812. Grade VI.
THE PIONEER TWINS. Grade VI.
THE AMERICAN TWINS OF THE REVOLUTION. Grade VII.
THE PURITAN TWINS. Grade VII.