diff --git a/src/bibapi/schemas/marcxml.py b/src/bibapi/schemas/marcxml.py
new file mode 100644
index 0000000..526e6f7
--- /dev/null
+++ b/src/bibapi/schemas/marcxml.py
@@ -0,0 +1,56 @@
+from dataclasses import dataclass, field
+from typing import List, Optional
+
+
+# --- MARC XML structures ---
+@dataclass
+class ControlField:
+    tag: str
+    value: str
+
+
+@dataclass
+class SubField:
+    code: str
+    value: str
+
+
+@dataclass
+class DataField:
+    tag: str
+    ind1: str = " "
+    ind2: str = " "
+    subfields: List[SubField] = field(default_factory=list)
+
+
+@dataclass
+class MarcRecord:
+    leader: str
+    controlfields: List[ControlField] = field(default_factory=list)
+    datafields: List[DataField] = field(default_factory=list)
+
+
+# --- SRU record wrapper ---
+@dataclass
+class Record:
+    recordSchema: str
+    recordPacking: str
+    recordData: MarcRecord
+    recordPosition: int
+
+
+@dataclass
+class EchoedSearchRequest:
+    version: str
+    query: str
+    maximumRecords: int
+    recordPacking: str
+    recordSchema: str
+
+
+@dataclass
+class SearchRetrieveResponse:
+    version: str
+    numberOfRecords: int
+    records: List[Record] = field(default_factory=list)
+    echoedSearchRetrieveRequest: Optional[EchoedSearchRequest] = None
diff --git a/src/bibapi/sru.py b/src/bibapi/sru.py
index 407435c..8cdda6a 100644
--- a/src/bibapi/sru.py
+++ b/src/bibapi/sru.py
@@ -1,6 +1,5 @@
 import re
 import xml.etree.ElementTree as ET
-from dataclasses import dataclass, field
 from enum import Enum
 from typing import Dict, Iterable, List, Optional, Tuple, Union
 
@@ -9,66 +8,21 @@ from requests.adapters import HTTPAdapter
 
 # centralized logging used via src.shared.logging
 from .schemas.bookdata import BookData
+from .schemas.marcxml import (
+    ControlField,
+    DataField,
+    EchoedSearchRequest,
+    MarcRecord,
+    Record,
+    SearchRetrieveResponse,
+    SubField,
+)
 
 # -----------------------
 # Dataclasses
 # -----------------------
 
 
-# --- MARC XML structures ---
-@dataclass
-class ControlField:
-    tag: str
-    value: str
-
-
-@dataclass
-class SubField:
-    code: str
-    value: str
-
-
-@dataclass
-class DataField:
-    tag: str
-    ind1: str = " "
-    ind2: str = " "
-    subfields: List[SubField] = field(default_factory=list)
-
-
-@dataclass
-class MarcRecord:
-    leader: str
-    controlfields: List[ControlField] = field(default_factory=list)
-    datafields: List[DataField] = field(default_factory=list)
-
-
-# --- SRU record wrapper ---
-@dataclass
-class Record:
-    recordSchema: str
-    recordPacking: str
-    recordData: MarcRecord
-    recordPosition: int
-
-
-@dataclass
-class EchoedSearchRequest:
-    version: str
-    query: str
-    maximumRecords: int
-    recordPacking: str
-    recordSchema: str
-
-
-@dataclass
-class SearchRetrieveResponse:
-    version: str
-    numberOfRecords: int
-    records: List[Record] = field(default_factory=list)
-    echoedSearchRetrieveRequest: Optional[EchoedSearchRequest] = None
-
-
 # -----------------------
 # Parser
 # -----------------------
@@ -433,11 +387,6 @@ class DNBData(Enum):
     NAME = "DNB"
 
 
-class SRUSite(Enum):
-    SWB = SWBData
-    DNB = DNBData
-
-
 RVK_ALLOWED = r"[A-Z0-9.\-\/]"  # conservative char set typically seen in RVK notations
 
 
@@ -562,8 +511,10 @@ class Api:
         # Best-effort cleanup
         self.close()
 
-    def get(self, query_args: Iterable[str]) -> List[Record]:
+    def get(self, query_args: Union[Iterable[str], str]) -> List[Record]:
         # if any query_arg ends with =, remove it
+        if isinstance(query_args, str):
+            query_args = [query_args]
         if self.site == "DNB":
             args = [arg for arg in query_args if not arg.startswith("pica.")]
             if args == []:
@@ -623,3 +574,11 @@ class SWB(Api):
         self.url = SWBData.URL.value
         self.prefix = SWBData.ARGSCHEMA.value
         super().__init__(self.site, self.url, self.prefix)
+
+
+class DNB(Api):
+    def __init__(self):
+        self.site = DNBData.NAME.value
+        self.url = DNBData.URL.value
+        self.prefix = DNBData.ARGSCHEMA.value
+        super().__init__(self.site, self.url, self.prefix)