Sources for the massacre of 436:

Prosperius Tiro 1322:
Eodem tempore Gundicharium Burgundionum regem intra Gallias habitantem Aetius bello obtrivit pacemque ei supplicanti dedit, qua non diu potitus est, siquidem illum Chunni cum populo suo ab stirpe deleverint.

Chronica Gallica 118:
Bellum contra Burgundionum gentem memorabile exarsit, quo universo paene gens cum rege per Aetium deleta.

Hydatius 108:
Burgundiones, qui rebellaverant, a Romanis duce Aetio debellantur.
Hydatius 110:
Narbona obsidione liberatur Aetio duce et magistro militum. Burgundionum caesa XX. milia.

Sidonius Apollinaris, Carmen VII, line 234/5.
I'm sorry, I don't have access to the exact Latin text at this moment.
It says something about Avitus helping Aetius in several cases, among which the time when the Burgundians plundered Belgica.

Prosperius, Hydatius and the writer of the Chronica Gallica are all writers of chronicles. Except for this fact, nothing is known about their lives.

Sidonius Apollinaris was a Gaulish nobleman of exalted rank. His father-in-law Avitus became Emperor in 455. Sidonius enlivened the occasion by composing a panegyric in his honour, known as Carmen VII.

All sources are edited in the Monumenta Germaniae Historiae (MGH).

In the near future, I will translate the Latin texts into English. (Or could some kind reader lend a helping hand?)

Narbo: Present Narbonne, in south-western France. In the fifth century an important provincial capital.

Aetius: Roman general who virtually ruled the western Empire from 435 to 454. Best known for his defeating Attila the Hun in 451.

Gregory of Tours was a late 6th century bishop of Tours, who wrote a general history. He is the main source for the 5th and 6th century history of Gaul and he describes the reigns of Clovis and his descendants: the Merovingian kings.

Gregory, when describing Clovis conquering yet another king, always mentions he took posession of his treasure.