Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System by Schwamb, M, Orosz, J, Carter, J, Welsh, W, Fischer, D, Torres, G, Howard, A, Crepp, JR, Keel, W, Lintott, C, Kaib, N, Terrell, D, Gagliano, R, Jek, K, Parrish, M, Smith, A, Lynn, S, Simpson, R, Giguere, M, Schawinski, K