Detailed Drawings > Working with Drawing Sketches > Specifying Drafting References > About Drafting References
  
About Drafting References
You can specify a drafting reference depending upon the type of draft entity that you want to create. The following drafting references are available on the Sketch tab, in the Controls group:
Angle
Offset
References
Radius
Start Tangency
End Tangency
Absolute Coordinates
Relative Coordinates