source: The exchange of copies of this Agreement by electronic mail in "portable document format"  form or by other similar electronic means shall constitute effective execution and delivery of this Agreement and shall have the same effect as copies executed and delivered with original signatures.
target: The exchange of copies of this Agreement is by electronic mail in "portable document format" form or by other similar electronic means. They shall constitute effective execution and delivery of this Agreement. They shall have the same effect as copies executed and delivered with original signatures.
references: The exchange of copies of this Agreement is by electronic mail in "portable document format" form or by other similar electronic means. They shall constitute effective execution and delivery of this Agreement. They shall have the same effect as copies executed and delivered with original signatures.