Richards, A.J.; Stephenson, J.H. (1984). Avionic Navigation Systems Specialist. Avionic Navigation Systems Specialist. Extension Course Institute, Air University. p. 169. Archivado desde el original el 30 de mayo de 2020. Consultado el 27 de septiembre de 2018.
«Bits From MRO Tools». mrotools.com. Archivado desde el original el 25 de abril de 2012. «The Frearson recess is designed so that any size bit will fit any size recess.»
"The Phillips screwdriver has about 30° flukes and a blunt end, while the Reed and Prince has 45° flukes and a sharper, pointed end." RECESSED www.tpub.comArchivado el 8 de abril de 2009 en Wayback Machine. October 2011
Richards, A.J.; Stephenson, J.H. (1984). Avionic Navigation Systems Specialist. Avionic Navigation Systems Specialist. Extension Course Institute, Air University. p. 169. Archivado desde el original el 30 de mayo de 2020. Consultado el 27 de septiembre de 2018.
"The Phillips screwdriver has about 30° flukes and a blunt end, while the Reed and Prince has 45° flukes and a sharper, pointed end." RECESSED www.tpub.comArchivado el 8 de abril de 2009 en Wayback Machine. October 2011
«Bits From MRO Tools». mrotools.com. Archivado desde el original el 25 de abril de 2012. «The Frearson recess is designed so that any size bit will fit any size recess.»