Enforce English language in all URLs

The logic assumed that the page is in English, but freeproxies can fetch
the page from different countries in their local language. This was
causing an error mentioned in #413.

Author: arunkannawadi

scholarly/_scholarly.py

@@ -18,7 +18,7 @@
 _PUBSEARCH = '/scholar?hl=en&q={0}'
 _CITEDBYSEARCH = '/scholar?hl=en&cites={0}'
 _ORGSEARCH = "/citations?view_op=view_org&hl=en&org={0}"
-_MANDATES_URL = "https://scholar.google.com/citations?view_op=mandates_leaderboard_csv"
+_MANDATES_URL = "https://scholar.google.com/citations?view_op=mandates_leaderboard_csv&hl=en"
 
 
 class _Scholarly:
@@ -485,7 +485,7 @@ def download_mandates_csv(self, filename: str, overwrite: bool = False,
                               "setting overwrite=True")
         text = self.__nav._get_page(_MANDATES_URL, premium=False)
         if include_links:
-            soup = self.__nav._get_soup("/citations?view_op=mandates_leaderboard")
+            soup = self.__nav._get_soup("/citations?hl=en&view_op=mandates_leaderboard")
             text = text.replace("Funder,", "Funder,Policy,Cached,", 1)
             for agency in soup.find_all("td", class_="gsc_mlt_t"):
                 cached = agency.find("span", class_="gs_a").a["href"]

scholarly/publication_parser.py

@@ -9,9 +9,9 @@
 _CITATIONPUB = '/citations?hl=en&view_op=view_citation&citation_for_view={0}'
 _SCHOLARPUB = '/scholar?hl=en&oi=bibs&cites={0}'
 _CITATIONPUBRE = r'citation_for_view=([\w-]*:[\w-]*)'
-_BIBCITE = '/scholar?q=info:{0}:scholar.google.com/\
+_BIBCITE = '/scholar?hl=en&q=info:{0}:scholar.google.com/\
 &output=cite&scirp={1}&hl=en'
-_CITEDBYLINK = '/scholar?cites={0}'
+_CITEDBYLINK = '/scholar?hl=en&cites={0}'
 _MANDATES_URL = '/citations?view_op=view_mandate&hl=en&citation_for_view={0}'
 
 _BIB_MAPPING = {