Erratum: Structure-Activity Profiles of Novel 6-Substituted Pyrrolo[2,3-d]pyrimidine Thienoyl Antifolates with Modified Amino Acids for Cellular Uptake by Folate Receptors α and β and the Proton-Coupled Folate Transporter (Journal of Medicinal Chemistry (2014) 57 (8152-8166) DOI: 10.1021/jm501113m)