How do you tell if a Alexande Calder litho signed in plate and numbered in pencil is real?

To determine if an Alexander Calder lithograph is authentic, first check for the quality of the print and the clarity of the lines, as genuine works will exhibit high craftsmanship. Examine the signature; if it's signed in the plate, it should be part of the print itself, while a pencil signature indicates it was hand-signed. Additionally, verify the numbering; authentic Calder lithographs are usually limited editions with clear, consistent numbering. Finally, consider obtaining a third-party appraisal or provenance documentation to further validate its authenticity.