Some refactoring...

Records.cs

@@ -13,7 +13,15 @@ namespace Txt2Bib.Records
         public string ToString();
     }
 
-    public record class ArticleBib : IBib
+    public abstract record ItemType
+    {
+        protected static bool IsDoi(string url)
+        {
+            return url.Contains("doi");
+        }
+    }
+
+    public record class Article : ItemType, IBib
     {
         public string Type { get; init; } = "article";
         public string[] Author { get; set; } = { "Gianni e Pinotto" };
@@ -64,11 +72,6 @@ namespace Txt2Bib.Records
             return ToString();
         }
 
-        private bool IsDoi(string url)
-        {
-            return url.Contains("doi");
-        }
-
         public override string ToString()
         {
             return $"@{Type}{{{Author[0][..5].Replace(". ", "_")}_{Year},\n" +
@@ -85,7 +88,7 @@ namespace Txt2Bib.Records
         }
     }
 
-    public record class BookBib : IBib
+    public record class Book : ItemType, IBib
     {
         public string Type { get; init; } = "book";
         public string[] Author { get; set; } = Array.Empty<string>();
@@ -128,15 +131,10 @@ namespace Txt2Bib.Records
             return ToString();
         }
 
-        private bool IsDoi(string url)
-        {
-            return url.Contains("doi");
-        }
-
         public override string ToString()
         {
-            var label = "";
-            var authString = "";
+            string label;
+            string authString;
 
             if (Author.Length != 0)
             {

Text2Bib.cs

@@ -15,7 +15,7 @@ namespace Txt2Bib
     /// </summary>
     public class Text2Bib
     {
-        private string[] _citTypes = { "J", "B", "C", "P", "?" };
+        private string[] _citTypes = { "J", "B", "C", "P", "I" };
         
         /// <summary>
         /// Generate single .bib file from input text files
@@ -41,7 +41,7 @@ namespace Txt2Bib
         /// <returns></returns>
         public string CreateBibTeX(string path)
         {
-            var reader = File.OpenText(path);
+            using var reader = File.OpenText(path);
             byte[] contentBytes = File.ReadAllBytes(path);
             var content = Encoding.Latin1.GetString(contentBytes);
 
@@ -82,8 +82,8 @@ namespace Txt2Bib
             {
                 citation = type switch
                 {
-                    "J" => (new ArticleBib()).Convert(lines),
-                    "B" => new BookBib().Convert(lines),
+                    "J" => (new Article()).Convert(lines),
+                    "B" => new Book().Convert(lines),
                     //"C" => new ChapterBib(),
                     //"P" => new ConferenceBib(),
                     _ => ""

Txt2Bib.csproj

@@ -5,7 +5,7 @@
     <TargetFramework>net6.0-windows</TargetFramework>
     <Nullable>enable</Nullable>
     <UseWPF>true</UseWPF>
-    <Version>0.1.0</Version>
+    <Version>0.1.1</Version>
   </PropertyGroup>
 
   <ItemGroup>