legislation_cosponsors: 111-sres-596, C001070

Cosponsors for tracked legislation. Distinguishes original cosponsors (signed on at introduction) from later additions. Linked to congress_members via bioguide_id.

This data as json

bill_id	bioguide_id	full_name	party	state	sponsorship_date	is_original_cosponsor
111-sres-596	C001070	Sen. Casey, Robert P., Jr. [D-PA]	D	PA	2010-07-28	1