Authors:

Almost any questions can be answered,cheaply, quickly and finally, by a test campaign. And that's he way to answer them - not by arguments around a table

Dr. Robert C. Worstell, Claude C. Hopkins, John E. Kennedy, Albert D. Lasker “Scientific Advertising Origins”, Lulu.com
Almost any questions can be answered,cheaply, quickly and finally, by a test campaign. And that's he way to answer them - not by arguments around a table