How to list Newsletter Studio newsletters on the front end

List newsletter on the front end

@using NewsletterStudio.Core.Model
@using NewsletterStudio.Infrastucture
@using NewsletterStudio.Infrastucture.Services
@using NewsletterStudio.Services.RenderTasks
@inherits Umbraco.Web.Mvc.UmbracoTemplatePage
@{
    Layout = null;
}
@{
    // This will give you all the newsletters thats listed in the "Sent"-folder in the backoffice. This means that they are not older than 90 days.
    var listOfNewslettersLast90Days = new NewsletterService(GlobalFactory.Current.NewsletterRepository).GetSent();
    
    // This will give you all letters that has been successfully sent.
    var listOfAllSentNewsletters = NewsletterStudio.Infrastucture.GlobalFactory.Current.NewsletterRepository.GetByStatus(new int[] { NewsletterStatus.Completed});
}
@if (Request.QueryString["id"] == null)
{
    <ul>
        @foreach (var item in listOfAllSentNewsletters)
        {
            <p>
                <a href="/?id=@item.Id">@item.Name</a>
            </p>
        }
    </ul>
}
else
{
    var letter = GlobalFactory.Current.NewsletterRepository.GetById(Convert.ToInt32(Request.QueryString["id"]));
    RenderEngine renderEngine = new RenderEngine(letter);
    
    @Html.Raw(renderEngine.RenderPreview())
}