I am working on a "related content" widget that shows the 3 latest articles with the same tags, with "latest" being determined by a custom field named "articleDate". I can't seem to figure out how to use custom fields in a query of the returned published content. Below is my attempt:

var publishedContent = Umbraco.TagQuery.GetContentByTag(tag);

    if (publishedContent.Where(p=>p.Id!=CurrentPage.Id).Count() > 0)
        {
@foreach (var item in publishedContent.Where(p=>p.Id!=CurrentPage.Id).OrderByDescending(p => p.articleDate).Take(3)) {
                        var page = Umbraco.Content(item.Id);
                        <li class="list-group-item">
                            <a href="@item.Url">@item.Name
                            <div class="articleDate">@page.articleDate.ToString("MMMM dd, yyyy")</div></a>
                        </li>
                    }
}