VEST MEASUREMENT                         

Place a cloth measuring tape just above your eyebrows and loosely measure round the circumference of your head. To ensure that the measurement is absolutely correct carefully repeat this procedure two or three times. If your measurement falls between sizes, select the next largest size. VEST MEASUREMENT

A to B = Back Shoulder?
E to F = Top Shoulder to End Bottum Point Length? 
C to D = Around Waist ?