3 daughter colonies of the 4a were tested:
CH-51-180-2955-1989 CH-51-182-2967-1989 CH-51-182-2968-1989
1 tested queens were mated at the mating station:
CH-51-182-3227-1990
1 daughter colonies of queens mated at the mating station were tested:
CH-51-182-3581-1991