Documented by Walter Schwarz, a British journalist and author, he observed that the traditional attire of the Yoruba and Hausa had become the basis of Nigeria's national dress. He also noted that by the 1960s, women from other ethnic groups had adopted the Yoruba womens gele.
I’m looking at the PDF for Sylvia Leith Ross right now, and there’s no single documentation of this claim so where did you get it from?