Ref1

http://khartoumspace.uofk.edu/bitstream/handle/123456789/11165/Potentialities%20of%20Indigo%20plant%20%28Indigofera%20tinctoria%29%20Production%20in%20the%20Sudan%20for%20Domestic%20Use%2C%20and%20Exportation.pdf?sequence=1&isAllowed=y