(1880). Summary of the labors of William J. Mullen, the prisoner's friend for the past 30 years: Wherein it is shown that Mr. Mullen has been instrumental in procuring a release from prison for more than 50,000 persons : this has been accomplished at a saving to the taxpayers of the city of Philadelphia of $570,432 50/100 as can be seen by a perusal of the agents' reports which is here given, during his connection with the Prison Society for the past 30 years. [Philadelphia, Pa.]: M.P. Summers & Co..

Summary of the Labors of William J. Mullen, the Prisoner's Friend for the Past 30 Years: Wherein It Is Shown That Mr. Mullen Has Been Instrumental in Procuring a Release From Prison for More Than 50,000 Persons : This Has Been Accomplished At a Saving to the Taxpayers of the City of Philadelphia of $570,432 50/100 As Can Be Seen By a Perusal of the Agents' Reports Which Is Here Given, During His Connection With the Prison Society for the Past 30 Years. [Philadelphia, Pa.]: M.P. Summers & Co., 1880.

Summary of the Labors of William J. Mullen, the Prisoner's Friend for the Past 30 Years: Wherein It Is Shown That Mr. Mullen Has Been Instrumental in Procuring a Release From Prison for More Than 50,000 Persons : This Has Been Accomplished At a Saving to the Taxpayers of the City of Philadelphia of $570,432 50/100 As Can Be Seen By a Perusal of the Agents' Reports Which Is Here Given, During His Connection With the Prison Society for the Past 30 Years. [Philadelphia, Pa.]: M.P. Summers & Co., 1880.