BALLOU, DONALD H.
Plane and spherical trigonometry with tables, by Donald H. Ballou & Frederick H. Steen.
BALLOU, DONALD H. Plane and spherical trigonometry with tables, by Donald H. Ballou & Frederick H. Steen. © 4Aug43; A177639. Donald H. Ballou & Frederick H. Steen (A); 8Sep70; R490917.
Donald H. Ballou & Frederick H. Steen|A