It is already in the text, there's no need for adding redundant sources. Additional sources are only needed if they provide new information or if they are considered (significantly) more reliable/reputable than the old ones.
Also it doesn't make sense to include every single whoonga related incident or drug bust, i.e. the article should concentrate to summarizes the most important knowledge about whoonga (things like: what is it made of, effects of its use on society or individuals, distribution/availability)