Addgene - pDONR221: [http://www.addgene.org/vector-database/2394/]
Invitrogen - pDONR221: [http://tools.invitrogen.com/content/sfs/manuals/gateway_pdonr_vectors.pdf]
pDONR221 Sequence: [http://tools.invitrogen.com/content/sfs/vectors/pdonr221_seq.txt]
