learned treatises

In order that a published treatise, periodical, or pamphlet on a
subject of law, history, science, or art may be admissible, it
is necessary either:
1. That the court can take judicial notice of it  or
2. A witness expert on the subject testifies that the writer of
   the statement in the treatise, periodical, or pamphlet is
   recognized in his profession or calling as expert in the

Reasons for admission
1. Necessity – even if such person is legally procurable, the
   expense is frequently disproportionate.
2. Trustworthiness – learned writers have no motive to misrepresent.
   He is aware that his work will be carefully scrutinized by the
   learned members of his profession and that he may be subject
   to criticisms and ultimately rejected as an authority of the
   subject matter if his conclusions are found to be invalid.

A published treatise/periodical/pamphlet on a subject of
history/law/science/art is admissible as tending to prove the
truth of a matter stated therein, if the court takes judicial
notice or a witness expert in the subject testifies that the
writer of the statement in the treatise/periodical/pamphlet is
recognized in his profession/calling as expert in the subject.