diff --git a/test/tests/utilities_itemTest.js b/test/tests/utilities_itemTest.js
index 4040320..4728361 100644
--- a/test/tests/utilities_itemTest.js
+++ b/test/tests/utilities_itemTest.js
@@ -318,6 +318,58 @@ describe("Zotero.Utilities.Item", function () {
 			];
 			checkSort(numbersInOrder);
 		});
+		
+		it("should correctly order RVK call numbers (Regensburger Verbundklassifikation)", function () {
+			let numbersInOrder = [
+				'NH 7000 T288-2,4,55',
+				'NH 7000 T288-2,32,5',
+				'NH 7000 T288-2,33,1',
+				'NH 7000 T288-2,33,2',
+				'NS 3293 W642-1',
+				'NS 3293 W642-1+1',
+				'NS 3293 W642-2',
+				'NS 3293 W828',
+				'NS 3293 W828(3)',
+				'NS 3293 W828(20)',
+				'PF 912',
+				'PF 912.307',
+				'PF 912.370'
+			];
+			checkSort(numbersInOrder);
+		});
+		
+		it("should correctly order BK call numbers (Basisklassifikation)", function () {
+			let numbersInOrder = [
+				'24.99',
+				'31',
+				'31.01',
+				'31.02',
+				'31.10'
+			];
+			checkSort(numbersInOrder);
+		});
+	
+		it("should correctly order call numbers containing a simple combination of a letter and an increasing number (numerus currens)", function () {
+			let numbersInOrder = [
+				'M 1',
+				'M 2',
+				'M 10',
+				'M 10a',
+				'M 11',
+				'M 100 b'
+			];
+			checkSort(numbersInOrder);
+			
+			numbersInOrder = [
+				'M1',
+				'M2',
+				'M10',
+				'M10a',
+				'M11',
+				'M100b'
+			];
+			checkSort(numbersInOrder);
+		});
 	});
 
 	describe("#languageToISO6391()", function () {
diff --git a/utilities_item.js b/utilities_item.js
index 8fc9021..14a158e 100644
--- a/utilities_item.js
+++ b/utilities_item.js
@@ -1030,7 +1030,7 @@ var Utilities_Item = {
 
 		let onlyNumbersRe = /^\d*$/;
 		let deweyRe = /^(\d{3})(?:\.(\d+))?(?:\/([a-zA-Z]{3}))?$/;
-		let lcWithClassificationRe = /^[a-zA-Z]{1,3}\d+($|(?=\s*[.\d]))/;
+		let lcWithClassificationRe = /^[a-zA-Z]{1,3}\d+($|(?=\s*(.|\s\d)))/;
 
 		if (onlyNumbersRe.test(fieldA) && onlyNumbersRe.test(fieldB)) {
 			return parseInt(fieldA) - parseInt(fieldB);
@@ -1067,7 +1067,7 @@ var Utilities_Item = {
 			}
 		}
 
-		return (fieldA > fieldB) ? 1 : (fieldA < fieldB) ? -1 : 0;
+		return Zotero.localeCompare(fieldA, fieldB);
 	}
 }