Classically, weak König's lemma and Brouwer's fan theorem for detachable bars are equivalent. We give a direct constructive proof that the former implies the latter.
"Weak König's Lemma Implies Brouwer's Fan Theorem: A Direct Proof." Notre Dame J. Formal Logic 47 (2) 249 - 252, 2006. https://doi.org/10.1305/ndjfl/1153858649