^Nitschke, Aleta A.; Frye, William D.; American Hotel & Lodging Educational Institute, . . (2015). Managing Housekeeping Operations with Answer Sheet (EI), Educational Institute. BiggerBooks. ISBN 9780133097085 (revised Aug 2023)
^Aleta A. Nitschke, William D. Frye, . . American Hotel amp; Lodging Educational Institute (2012). Managing Housekeeping Operations With Answer Sheet (ei), Pearson Education. Indigo. ISBN 9780133097085 (revised Jun 2016)