C++ Code from Scott Campbell, shared on GIT under MIT License with permission of the author, July 2019
The following files acquired directly from the original author's archive: ELCOR.CPP Elfind.cpp SATFIT.CPP SATID.CPP
http://sat.belastro.net/satelliteorbitdetermination.com/DPFIT.22.zip DPFIT.22 32378.txt 90025.txt dp.obs DPFIT.CPP DPFIT.exe ivan.obs r90027f1.txt r90027f2.txt readme.txt
http://sat.belastro.net/satelliteorbitdetermination.com/ELCORD.14.zip ELCORD.14/ ELCOR.CPP ELCOR.H ELCORD.dev ELCORD.exe GETEL.CPP GETOBS.CPP GETSITES.CPP MATRIX.CPP SDP4.CPP SDP4.offset.CPP
INCLUDE/ http://sat.belastro.net/satelliteorbitdetermination.com/SOURCE_CODE.zip DATE.h orbit.h orbit_gray.h sst.h - http://sat.belastro.net/satelliteorbitdetermination.com/SST.8.zip
MISC/ http://sat.belastro.net/satelliteorbitdetermination.com/RV2TLE.8.ZIP RV2TLE.8 orbit_gray.h RV2TLE_KM.CPP RV2TLE_KM.exe RV2TLE.CPP RV2TLE.exe VEC_KM.TXT VEC.TXT
http://sat.belastro.net/satelliteorbitdetermination.com/SATTIME.zip SATTIME SatTime.cpp SatTime.exe
http://sat.belastro.net/satelliteorbitdetermination.com/ HISTORY.zip SATS.zip STATIONS.IN (from SATFIT.31.zip)
http://sat.belastro.net/satelliteorbitdetermination.com/SATFIT.31.zip SATFIT.31 ELCORD.exe Elfind.exe SATFIT.exe
http://sat.belastro.net/satelliteorbitdetermination.com/SST.8.zip SST.8 advance.txt DATE.h SST.CPP SST.exe th0.pdf
UTIL/ CLAS2SAT.cpp FIX96.cpp MERGE.cpp OBS2SAT.CPP SATS2FILE.cpp SATS2HISTORY.cpp TrendA.cpp
http://sat.belastro.net/satelliteorbitdetermination.com/SSR.zip SSR std-mag.dat SSR.ID