Big Bird: Transformers for Longer Sequences - Zaheer, Manzil; Guruganesh, Guru; Dubey, Kumar Avinava; Ainslie, Joshua; Alberti, Chris; Ontanon, Santiago; Pham, Philip; Ravula, Anirudh; Wang, Qifan; Yang, Li; Ahmed, Amr (Advances in Neural Information Processing Systems, 2020)