OK: Grove 4 has two entries, as follows:
- Vol.2: "Op.73 Violin Concerto in A minor" (wrong opus number)
- Supp. Vol: "Op.82 Violin Concerto in A" (wrong key)
I suggest that these two entries actually refer to the same work. Glazunov's Op.73 is in fact his
Solemn Overture for orchestra (1900). The (single) entry should read:
"Op.82 Violin Concerto in A minor"
It is surely a case of two wrong entries - or maybe the VC originally had a different opus number which was later changed. At all events, there is absolutely no mention anywhere of another VC - see this full list of his works:
http://home.wanadoo.nl/ovar/glazun.htm