  Many legal professionals think that the explosion of information about local,
regional, national, and international legislation makes their practice more
costly, time-consuming, and even error-prone. The two main reasons for this are
that most legislation is usually unstructured, and the tremendous amount and
pace with which laws are released causes information overload in their daily
tasks. In the case of the legal domain, the research community agrees that a
system allowing to generate automatic responses to legal questions could
substantially impact many practical implications in daily activities. The
degree of usefulness is such that even a semi-automatic solution could
significantly help to reduce the workload to be faced. This is mainly because a
Question Answering system could be able to automatically process a massive
amount of legal resources to answer a question or doubt in seconds, which means
that it could save resources in the form of effort, money, and time to many
professionals in the legal sector. In this work, we quantitatively and
qualitatively survey the solutions that currently exist to meet this challenge.
