private IEnumerable <ArticleItemViewModel> GetArticles() { if (this.ReferenceDate != null) { return(ArticleModel.GetAuthorArticlesByMonth(this.Author.Slug, this.ReferenceDate.Reference) .Select(a => new ArticleItemViewModel(a))); } return(ArticleModel.GetRecentArticlesByAuthor(this.Author.Slug) .Select(a => new ArticleItemViewModel(a))); }