Things Great and Small: Collections Management Policies (2nd edition). John E. Simmons. (Rowman and LIttlefield, 2018)
Registration Methods for Small History Museums (5th edition). Daniel B. Reibel. (American Association for State and Local History, 2018)
A Legal Primer on Managing Museum Collections (3rd edition). Marie C. Malaro and Ildiko Pogany DeAngelis. (Smithsonian Books, 2012)
Museum Registration Methods (3rd edition). Dorothy H. Dudley, Irma Berzold Wilkinson et al (AAM 1979)
(Later editions include updated information about digitization, etc.)
Managing Previously Unmanaged Collections: A Practical Guide for Museums. Angela Kipp (Rowman and Littlefield, 2016).