Não informado. (1969). Progressive Horticulture. Hill Horticulture Development Board, Horticultural Experiments and Training.
Chicago-referens (17:e uppl.)Não informado. Progressive Horticulture. Chaubattia, India: Hill Horticulture Development Board, Horticultural Experiments and Training, 1969.
MLA-referens (8:e uppl.)Não informado. Progressive Horticulture. Hill Horticulture Development Board, Horticultural Experiments and Training, 1969.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.