Crane, Eva; Walker, Penelope. (1984). Pollination directory for world crops / Eva Crane and Penelope Walker. London :: International Bee Research Association,.
Crane, Eva; Walker, Penelope. Pollination directory for world crops / Eva Crane and Penelope Walker. London :: International Bee Research Association,, 1984
Crane, Eva; Walker, Penelope. Pollination directory for world crops / Eva Crane and Penelope Walker. London :: International Bee Research Association,, 1984.