Distance Determinations: https://www.firearmsid.com/A_distance.htm

Distance Determinations: https://www.firearmsid.com/A_distance.htm
Distance: Bullet Holes: https://www.firearmsid.com/A_distbulletholes.htm
Distance: Gunshot Residue: https://www.firearmsid.com/A_distanceGSR.htm
Distance: Gunshot Residue Examination: https://www.firearmsid.com/A_distanceExams.htm
Distance: Gunshot Residue Standards: https://www.firearmsid.com/A_diststandards.htm
Distance: Gunshot Residue Test Results: https://www.firearmsid.com/A_distanceResults.htm
Distance: Shotgun Pattern Testing: https://www.firearmsid.com/A_distshotpatt.htm
On the NFSTC firearms training website read the following module:
Module 12:Gunshot Residue and Distance Determination: http://projects.nfstc.org/firearms/module12/fir_m12.htm
A Protocol for Gunshot Residue Examinations in Muzzle-to-target Distance Determinations by John H. Dillon, AFTE Journal, 1990, page 257.
A Protocol for Shot Pattern Examinations in Muzzle-to-Target Distance Determinations by John Dillon, AFTE Journal, 1991, p. 511
Comparison of 10,000 Consecutively Fired Cartridge Cases From a Model 22 Glock .40 S&W Caliber Semiautomatic Pistol, Jan Gouwe, AFTE Journal, 2008, 40, 1, 57-63.