ConcurrentBag<Entry> entrybag = new ConcurrentBag<Entry>(entries);
Console.WriteLine("Getting Wikibase Item Ids...");
Parallel.ForEach<Entry>(entrybag, (entry) =>
{
    entry.WikibaseItemId = GetWikibaseItemId(entry).Result;
});

async static Task<String> GetWikibaseItemId(Entry entry)
{
    using (var client = new HttpClient(new HttpClientHandler { AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate }))
    {
        client.BaseAddress = new Uri("https://en.wikipedia.org/w/api.php");
        entry.Title.Replace("+", "Plus");
        entry.Title.Replace("&", "and");
        String queryString = "?action=query&prop=pageprops&ppprop=wikibase_item&format=json&redirects=1&titles=" + entry.Title;
        queryString = queryString.Replace("+", "Plus");
        HttpResponseMessage response = await client.GetAsync(queryString);

        response.EnsureSuccessStatusCode();

        String result = response.Content.ReadAsStringAsync().Result;
        dynamic deserialized = JsonConvert.DeserializeObject(result);
        String data = deserialized.ToString();
        try
        {
            if (data.Contains("wikibase_item"))
            {
                return deserialized["query"]["pages"]["" + entry.PageId + ""]["pageprops"]["wikibase_item"].ToString();
            }
            else
            {
                return "NONE";
            }
        }
        catch (RuntimeBinderException)
        {
            return "NULL";
        }
        catch (Exception)
        {
            return "ERROR";
        }
    }
}

public class Entry
{
    public EntryCategory Category { get; set; }
    public int PageId { get; set; }
    public String Title { get; set; }
    public String WikibaseItemId { get; set; }
}