这个圈套... 2个句子代表关注的病例：

text = "He lives in Nidarvoll and tonight i must reach a train to Oslo at 6 oclock. The system, called BusTUC is built upon the classical system CHAT-80 (Warren and Pereira, 1982). CHAT-80 was a state of the art natural language system that was impressive on its own merits."

t2 = "He lives in Nidarvoll and tonight i must reach a train to Oslo at 6 oclock. The system, called BusTUC is built upon the classical system CHAT-80 (Warren and Pereira, 1982) fgbhdr was a state of the art natural. CHAT-80 was a state of the art natural language system that was impressive on its own merits."

首先，在引文位于句子结尾的情况下进行匹配：

p1 = "\. (.*\([A-za-z]+ .* [0-9]+\)\.+?)"

当引文不在句末时匹配：

p2 = "\. (.*\([A-za-z]+ .* [0-9]+\)[^\.]+\.+?)"

将这两种情况与“|'正则表达式运算符：

p_main = re.compile("\. (.*\([A-za-z]+ .* [0-9]+\)\.+?)"
                "|\. (.*\([A-za-z]+ .* [0-9]+\)[^\.]+\.+?)")

运行：

>>> print(re.findall(p_main, text))
[('The system, called BusTUC is built upon the classical system CHAT-80 (Warren and Pereira, 1982).', '')]

>>>print(re.findall(p_main, t2))
[('', 'The system, called BusTUC is built upon the classical system CHAT-80 (Warren and Pereira, 1982) fgbhdr was a state of the art natural.')]

在这两种情况下，你得到的句子与引文。
一个很好的资源是python正则表达式documentation和附带的regex howto页面。
干杯

text = "He lives in Nidarvoll and tonight i must reach a train to Oslo at 6 oclock. The system, called BusTUC is built upon the classical system CHAT-80 (Warren and Pereira, 1982). CHAT-80 was a state of the art natural language system that was impressive on its own merits."

你可以将文本分成一系列句子，然后选择以“）”结尾的句子。

sentences = text.split(".")[:-1]

for sentence in sentences:
    if sentence[-1] == ")":
        print sentence