Fixes bug in /reference/:id endpoints where makeExternalURL was undefined.
Fixes bug in /reference/:id endpoints where makeExternalURL was undefined.

kshefchek/monarch-app,monarch-initiative/monarch-app,jmcmurry/monarch-app,jmcmurry/monarch-app,DoctorBud/monarch-app,jmcmurry/monarch-app,kshefchek/monarch-app,monarch-initiative/monarch-app,DoctorBud/monarch-app,DoctorBud/monarch-app,jmcmurry/monarch-app,kshefchek/monarch-app,monarch-initiative/monarch-app,kshefchek/monarch-app,monarch-initiative/monarch-app,jmcmurry/monarch-app,kshefchek/monarch-app,DoctorBud/monarch-app,monarch-initiative/monarch-app,DoctorBud/monarch-app