TY  - BOOK
AU  - Sandi Metz
TI  - Practical object-oriented design an agile primer using ruby 
SN  - 13: 978-0-13-445647-8
U1  - Cir. 005.117 SA194 C2019 
PY  - 2019///
CY  - Boston, USA 
PB  - Pearson education, Inc. 
ER  -