What is the optimal regimen for BCG intravesical therapy? Are six weekly instillations necessary?, Zlotta, A R., Van Vooren J P., Huygen K, Drowart A, Decock M, Pirson M, Jurion Fabienne, Palfliet K, Denis Olivier J., Simon J, et al. , Eur Urol, 2000 Apr, Volume 37, Issue 4, (2000)