RT Journal Article SR Electronic(1) A1 Powell, Roger YR 2012 T1 How to… JF BSAVA Companion VO 2012 IS 4 SP 14 OP 18 DO https://doi.org/10.22233/20412495.0412.14 UL https://www.bsavalibrary.com/content/journals/10.22233/20412495.0412.14