Negotiable Instruments Law
Section 36. "When indorsement restrictive.- An indorsement is restrictive which either-
(a) Prohibits the further negotiation of the instrument; or
(b) Constitutes the indorsee the agent of the indorser; or
(c) Vests the title in the indorsee in trust for or to the use of some other person.
But the mere absence of words implying power to negotiate does not make an indorsement restrictive.