Supervision of cases with non-negative roentgenphotography; attempt at establishing the medical course of 2,490 cases whose x-rays were non-negative in x-ray examinations
Vigilancia de casos con roentgenfotografia no negativa; una tentativa de establecer el destino sanitario de 2.490 casos cuyas roentgenfotografias, no fueron negativas en encuestas roentgenfotografias