Nulls in cited patents

The uspto (and hence patentsview) has full data for patents issued in 1976 and above. Only a handful of fields are available for pre 1976 patents at uspto.gov (issue date, uspcs, cpcs and obviously patent number). The reference table below is copied from uspto.gov for patent D756514 If you compare the reference table to the patentsview data for that patent you'll see that the nulls returned by patentsview correspond to the pre 1976 patents referenced. It makes sense that the titles wouldn't come back but at a minimum I think the patent number should be returned.

Patents Cited in D756514
563421	July 1896	Sheppard
3247324	April 1966	Cefaly et al.
3618697	November 1971	Littmann et al.
D379935	June 1997	Jornacion
6883639	April 2005	Lam et al.
D536448	February 2007	Jackson

Data returned by patentsview