How to do it in python in case anyone is wondering:
import requests
import json
url = 'http://data.crossref.org/10.1017/S0022112061000019'
headers = {'Accept': 'application/citeproc+json'}
r = requests.get(url, headers=headers)
meta = json.loads(r.content)
# meta is a dictionary of metadata, e.g. meta['DOI']
