TY - JOUR T1 - Drug patent protection: How long is long enough? JF - Canadian Medical Association Journal JO - CMAJ SP - 1331 LP - 1331 VL - 164 IS - 9 AU - Barbara Sibbald Y1 - 2001/05/01 UR - http://www.cmaj.ca/content/164/9/1331.1.abstract ER -