At the flick of a switch : papers given at the Eleventh Eastern Regional Growers Conference held at the Hertfordshire College of Agriculture and Horticulture on 4th-6th January 1969 /
Eastern Regional Growers Conference(11th :1969 :Hertfordshire College of Agriculture and Horticulture)
Brown, Marion.
Barley, C. M.
Hertfordshire College of Agriculture and Horticulture.
Oaklands, [St Albans] :  Hertfordshire College of Agriculture & Horticulture, 
1969.