TY  - BOOK
AU  - Head, George O.
AU  - Pietra, Charles A.
AU  - Segal, Kenneth J L.
TI  - Autocad 3d book: : covers through AutoCAD release 12 
U1  - 620.00420285  
PY  - 1994///
CY  - New Delhi
PB  - Galgotia Publications Pvt Ltd
KW  - AutoCAD's user coordinate system
KW  - Surfaces and meshes
KW  - New twists to old commands
ER  -