Reference for Sanhedrin 35:5
מתני׳ <big><strong>כהן</strong></big> גדול דן ודנין אותו מעיד ומעידין אותו חולץ וחולצין לאשתו ומייבמין את אשתו אבל הוא אינו מייבם מפני שהוא אסור באלמנה
MAY BE PERFORMED TO HIS WIFE; HE HOWEVER, MAY NOT, PERFORM THAT DUTY, SINCE HE IS FORBIDDEN TO MARRY A WIDOW.<span class="x" onmousemove="('comment',' Lev. XXI, 14. A widow, or one divorced, or a profaned woman, or a harlot, these shall he not take. ');"><sup>8</sup></span> IF A DEATH HAPPENS IN HIS FAMILY, HE MUST NOT WALK IMMEDIATELY BEHIND THE BIER,<span class="x" onmousemove="('comment',' Though by following the bier, he would not come in actual contact with the dead: (v. p. 18, n. 7), precautions had to be taken so as to prevent any possibility of his becoming levitically impure. ');"><sup>9</sup></span>