diff --git a/SynonymGroup.ts b/SynonymGroup.ts
index 2b63e77..3bbb53c 100644
--- a/SynonymGroup.ts
+++ b/SynonymGroup.ts
@@ -67,10 +67,19 @@ type Treatments = {
   dpr: Set<Treatment>;
   cite: Set<Treatment>;
 };
+
+/**
+ * Describes a taxon-concept and why it is considered a synonym by synolib
+ */
 export type JustifiedSynonym = {
   taxonConceptUri: string;
   taxonName: TaxonName;
   /** Human-readable authority */ taxonConceptAuthority?: string;
+  /**
+   * Catalogue of Life Taxon URIs
+   * @example `["https://www.catalogueoflife.org/data/taxon/TWFG"]`
+   */
+  colID: string[];
   justifications: JustificationSet;
   treatments: Treatments;
   loading: boolean;
@@ -162,6 +171,13 @@ export default class SynonymGroup implements AsyncIterable<JustifiedSynonym> {
 
   private controller = new AbortController();
 
+  /**
+   * Constructs a SynonymGroup
+   *
+   * @param sparqlEndpoint SPARQL-Endpoint to query
+   * @param taxonName either a string of the form "Genus species infraspecific" (species & infraspecific names optional), or an URI of a http://filteredpush.org/ontologies/oa/dwcFP#TaxonConcept or a CoL taxon URI
+   * @param [ignoreRank=false] if taxonName is "Genus" of "Genus species", by default it will ony search for taxons of rank genus/species. If set to true, sub-taxa are also considered as staring points.
+   */
   constructor(
     sparqlEndpoint: SparqlEndpoint,
     taxonName: string,
@@ -366,26 +382,41 @@ SELECT DISTINCT ?url ?description WHERE {
         taxonName: string,
       ): Promise<JustifiedSynonym[]> => {
         if (fetchInit.signal.aborted) return Promise.resolve([]);
-        const [genus, species, subspecies] = taxonName.split(" ");
-        // subspecies could also be variety
-        // ignoreRank has no effect when there is a 'subspecies', as this is assumed to be the lowest rank & should thus not be able to return results in another rank
+        let taxonNameQuery = "";
+        if (taxonName.startsWith("http")) {
+          if (taxonName.includes("catalogueoflife.org")) {
+            taxonNameQuery =
+              `?tc <http://www.w3.org/2000/01/rdf-schema#seeAlso> <${taxonName}> .`;
+          } else {
+            taxonNameQuery = `BIND(<${taxonName}> as ?tc)`;
+          }
+        } else {
+          const [genus, species, subspecies] = taxonName.split(" ");
+          // subspecies could also be variety
+          // ignoreRank has no effect when there is a 'subspecies', as this is assumed to be the lowest rank & should thus not be able to return results in another rank
+          taxonNameQuery = `?tc dwc:genus "${genus}" .`;
+          if (species) taxonNameQuery += ` ?tc dwc:species "${species}" .`;
+          if (subspecies) {
+            taxonNameQuery +=
+              ` ?tc (dwc:subspecies|dwc:variety) "${subspecies}" .`;
+          }
+          if (!subspecies && !ignoreRank) {
+            taxonNameQuery += ` ?tc dwc:rank "${
+              species ? "species" : "genus"
+            }" .`;
+          }
+        }
         const query = `PREFIX cito: <http://purl.org/spar/cito/>
 PREFIX dc: <http://purl.org/dc/elements/1.1/>
 PREFIX dwc: <http://rs.tdwg.org/dwc/terms/>
 PREFIX treat: <http://plazi.org/vocab/treatment#>
 SELECT DISTINCT
-  ?tn ?name ?tc (group_concat(DISTINCT ?auth; separator=" / ") as ?authority) (group_concat(DISTINCT ?aug;separator="|") as ?augs) (group_concat(DISTINCT ?def;separator="|") as ?defs) (group_concat(DISTINCT ?dpr;separator="|") as ?dprs) (group_concat(DISTINCT ?cite;separator="|") as ?cites) (group_concat(DISTINCT ?trtn;separator="|") as ?trtns) (group_concat(DISTINCT ?citetn;separator="|") as ?citetns)
+  ?tn ?name ?tc (group_concat(DISTINCT ?auth; separator=" / ") as ?authority) (group_concat(DISTINCT ?colid; separator="|") as ?colids) (group_concat(DISTINCT ?aug;separator="|") as ?augs) (group_concat(DISTINCT ?def;separator="|") as ?defs) (group_concat(DISTINCT ?dpr;separator="|") as ?dprs) (group_concat(DISTINCT ?cite;separator="|") as ?cites) (group_concat(DISTINCT ?trtn;separator="|") as ?trtns) (group_concat(DISTINCT ?citetn;separator="|") as ?citetns)
 WHERE {
-  ?tc dwc:genus "${genus}";
-      treat:hasTaxonName ?tn;
-      ${species ? `dwc:species "${species}";` : ""}
-      ${subspecies ? `(dwc:subspecies|dwc:variety) "${subspecies}";` : ""}
-      ${
-          ignoreRank || !!subspecies
-            ? ""
-            : `dwc:rank "${species ? "species" : "genus"}";`
-        }
+  ${taxonNameQuery}
+  ?tc treat:hasTaxonName ?tn ;
       a <http://filteredpush.org/ontologies/oa/dwcFP#TaxonConcept>.
+  OPTIONAL { ?tc <http://www.w3.org/2000/01/rdf-schema#seeAlso> ?colid . }
   ?tn dwc:genus ?genus .
   OPTIONAL { ?tn dwc:subGenus ?subgenus . }
   OPTIONAL {
@@ -413,7 +444,7 @@ GROUP BY ?tn ?name ?tc`;
           .then(
             (json: SparqlJson) =>
               json.results.bindings.filter((t) => (t.tc && t.tn))
-                .map((t) => {
+                .map((t): JustifiedSynonym => {
                   return {
                     taxonConceptUri: t.tc.value,
                     taxonName: makeTaxonName(
@@ -423,6 +454,11 @@ GROUP BY ?tn ?name ?tc`;
                       t.citetns?.value.split("|"),
                     ),
                     taxonConceptAuthority: t.authority?.value,
+                    colID: t.colids?.value.split("|").filter((s) =>
+                      s.startsWith(
+                        "https://www.catalogueoflife.org/data/taxon/",
+                      )
+                    ),
                     justifications: new JustificationSet([
                       `${t.tc.value} matches "${taxonName}"`,
                     ]),
@@ -450,10 +486,11 @@ PREFIX dc: <http://purl.org/dc/elements/1.1/>
 PREFIX dwc: <http://rs.tdwg.org/dwc/terms/>
 PREFIX treat: <http://plazi.org/vocab/treatment#>
 SELECT DISTINCT
-  ?tc (group_concat(DISTINCT ?auth; separator=" / ") as ?authority) (group_concat(DISTINCT ?aug;separator="|") as ?augs) (group_concat(DISTINCT ?def;separator="|") as ?defs) (group_concat(DISTINCT ?dpr;separator="|") as ?dprs) (group_concat(DISTINCT ?cite;separator="|") as ?cites)
+  ?tc (group_concat(DISTINCT ?auth; separator=" / ") as ?authority) (group_concat(DISTINCT ?colid; separator="|") as ?colids) (group_concat(DISTINCT ?aug;separator="|") as ?augs) (group_concat(DISTINCT ?def;separator="|") as ?defs) (group_concat(DISTINCT ?dpr;separator="|") as ?dprs) (group_concat(DISTINCT ?cite;separator="|") as ?cites)
 WHERE {
   ?tc treat:hasTaxonName <${taxon.taxonName.uri}> .
   OPTIONAL { ?tc dwc:scientificNameAuthorship ?auth . }
+  OPTIONAL { ?tc <http://www.w3.org/2000/01/rdf-schema#seeAlso> ?colid . }
   OPTIONAL { ?aug treat:augmentsTaxonConcept ?tc . }
   OPTIONAL { ?def treat:definesTaxonConcept ?tc . }
   OPTIONAL { ?dpr treat:deprecates ?tc . }
@@ -481,6 +518,9 @@ GROUP BY ?tc`;
                   taxonConceptUri: t.tc.value,
                   taxonName: taxon.taxonName,
                   taxonConceptAuthority: t.authority?.value,
+                  colID: t.colids?.value.split("|").filter((s) =>
+                    s.startsWith("https://www.catalogueoflife.org/data/taxon/")
+                  ),
                   justifications: new JustificationSet([{
                     toString: () =>
                       `${t.tc.value} has taxon name ${taxon.taxonName.uri}`,
@@ -508,7 +548,7 @@ PREFIX dc: <http://purl.org/dc/elements/1.1/>
 PREFIX dwc: <http://rs.tdwg.org/dwc/terms/>
 PREFIX treat: <http://plazi.org/vocab/treatment#>
 SELECT DISTINCT
-  ?tn ?name ?tc (group_concat(DISTINCT ?auth; separator=" / ") as ?authority) (group_concat(DISTINCT ?justification; separator="|") as ?justs) (group_concat(DISTINCT ?aug;separator="|") as ?augs) (group_concat(DISTINCT ?def;separator="|") as ?defs) (group_concat(DISTINCT ?dpr;separator="|") as ?dprs) (group_concat(DISTINCT ?cite;separator="|") as ?cites) (group_concat(DISTINCT ?trtn;separator="|") as ?trtns) (group_concat(DISTINCT ?citetn;separator="|") as ?citetns)
+  ?tn ?name ?tc (group_concat(DISTINCT ?auth; separator=" / ") as ?authority) (group_concat(DISTINCT ?colid; separator="|") as ?colids) (group_concat(DISTINCT ?justification; separator="|") as ?justs) (group_concat(DISTINCT ?aug;separator="|") as ?augs) (group_concat(DISTINCT ?def;separator="|") as ?defs) (group_concat(DISTINCT ?dpr;separator="|") as ?dprs) (group_concat(DISTINCT ?cite;separator="|") as ?cites) (group_concat(DISTINCT ?trtn;separator="|") as ?trtns) (group_concat(DISTINCT ?citetn;separator="|") as ?citetns)
 WHERE {
   ?justification treat:deprecates <${taxon.taxonConceptUri}> ;
                  (treat:augmentsTaxonConcept|treat:definesTaxonConcept) ?tc .
@@ -522,6 +562,7 @@ WHERE {
   }
   BIND(CONCAT(?genus, COALESCE(CONCAT(" (",?subgenus,")"), ""), COALESCE(CONCAT(" ",?species), ""), COALESCE(CONCAT(" ", ?subspecies), ""), COALESCE(CONCAT(" var. ", ?variety), "")) as ?name)
   OPTIONAL { ?tc dwc:scientificNameAuthorship ?auth . }
+  OPTIONAL { ?tc <http://www.w3.org/2000/01/rdf-schema#seeAlso> ?colid . }
   OPTIONAL { ?aug treat:augmentsTaxonConcept ?tc . }
   OPTIONAL { ?def treat:definesTaxonConcept ?tc . }
   OPTIONAL { ?dpr treat:deprecates ?tc . }
@@ -539,41 +580,46 @@ GROUP BY ?tn ?name ?tc`;
           ).then((
             json: SparqlJson,
           ) =>
-            json.results.bindings.filter((t) => t.tc).map((t) => {
-              return {
-                taxonConceptUri: t.tc.value,
-                taxonName: makeTaxonName(
-                  t.tn.value,
-                  t.name?.value,
-                  t.trtns?.value.split("|"),
-                  t.citetns?.value.split("|"),
-                ),
-                taxonConceptAuthority: t.authority?.value,
-                justifications: new JustificationSet(
-                  t.justs?.value.split("|").map((url) => {
-                    if (!this.treatments.has(url)) {
-                      this.treatments.set(url, {
-                        url,
-                        details: getTreatmentDetails(url),
-                      });
-                    }
-                    return {
-                      toString: () =>
-                        `${t.tc.value} deprecates ${taxon.taxonConceptUri} according to ${url}`,
-                      precedingSynonym: taxon,
-                      treatment: this.treatments.get(url),
-                    };
-                  }),
-                ),
-                treatments: {
-                  def: makeTreatmentSet(t.defs?.value.split("|")),
-                  aug: makeTreatmentSet(t.augs?.value.split("|")),
-                  dpr: makeTreatmentSet(t.dprs?.value.split("|")),
-                  cite: makeTreatmentSet(t.cites?.value.split("|")),
-                } as Treatments,
-                loading: true,
-              };
-            }), (error) => {
+            json.results.bindings.filter((t) => t.tc).map(
+              (t): JustifiedSynonym => {
+                return {
+                  taxonConceptUri: t.tc.value,
+                  taxonName: makeTaxonName(
+                    t.tn.value,
+                    t.name?.value,
+                    t.trtns?.value.split("|"),
+                    t.citetns?.value.split("|"),
+                  ),
+                  taxonConceptAuthority: t.authority?.value,
+                  colID: t.colids?.value.split("|").filter((s) =>
+                    s.startsWith("https://www.catalogueoflife.org/data/taxon/")
+                  ),
+                  justifications: new JustificationSet(
+                    t.justs?.value.split("|").map((url) => {
+                      if (!this.treatments.has(url)) {
+                        this.treatments.set(url, {
+                          url,
+                          details: getTreatmentDetails(url),
+                        });
+                      }
+                      return {
+                        toString: () =>
+                          `${t.tc.value} deprecates ${taxon.taxonConceptUri} according to ${url}`,
+                        precedingSynonym: taxon,
+                        treatment: this.treatments.get(url),
+                      };
+                    }),
+                  ),
+                  treatments: {
+                    def: makeTreatmentSet(t.defs?.value.split("|")),
+                    aug: makeTreatmentSet(t.augs?.value.split("|")),
+                    dpr: makeTreatmentSet(t.dprs?.value.split("|")),
+                    cite: makeTreatmentSet(t.cites?.value.split("|")),
+                  } as Treatments,
+                  loading: true,
+                };
+              },
+            ), (error) => {
             console.warn("SPARQL Error: " + error);
             return [];
           });
@@ -585,7 +631,7 @@ PREFIX dc: <http://purl.org/dc/elements/1.1/>
 PREFIX dwc: <http://rs.tdwg.org/dwc/terms/>
 PREFIX treat: <http://plazi.org/vocab/treatment#>
 SELECT DISTINCT
-  ?tn ?name ?tc (group_concat(DISTINCT ?auth; separator=" / ") as ?authority) (group_concat(DISTINCT ?justification; separator="|") as ?justs) (group_concat(DISTINCT ?aug;separator="|") as ?augs) (group_concat(DISTINCT ?def;separator="|") as ?defs) (group_concat(DISTINCT ?dpr;separator="|") as ?dprs) (group_concat(DISTINCT ?cite;separator="|") as ?cites) (group_concat(DISTINCT ?trtn;separator="|") as ?trtns) (group_concat(DISTINCT ?citetn;separator="|") as ?citetns)
+  ?tn ?name ?tc (group_concat(DISTINCT ?auth; separator=" / ") as ?authority) (group_concat(DISTINCT ?colid; separator="|") as ?colids) (group_concat(DISTINCT ?justification; separator="|") as ?justs) (group_concat(DISTINCT ?aug;separator="|") as ?augs) (group_concat(DISTINCT ?def;separator="|") as ?defs) (group_concat(DISTINCT ?dpr;separator="|") as ?dprs) (group_concat(DISTINCT ?cite;separator="|") as ?cites) (group_concat(DISTINCT ?trtn;separator="|") as ?trtns) (group_concat(DISTINCT ?citetn;separator="|") as ?citetns)
 WHERE {
   ?justification (treat:augmentsTaxonConcept|treat:definesTaxonConcept) <${taxon.taxonConceptUri}> ;
                  treat:deprecates ?tc .
@@ -599,6 +645,7 @@ WHERE {
   }
   BIND(CONCAT(?genus, COALESCE(CONCAT(" (",?subgenus,")"), ""), COALESCE(CONCAT(" ",?species), ""), COALESCE(CONCAT(" ", ?subspecies), ""), COALESCE(CONCAT(" var. ", ?variety), "")) as ?name)
   OPTIONAL { ?tc dwc:scientificNameAuthorship ?auth . }
+  OPTIONAL { ?tc <http://www.w3.org/2000/01/rdf-schema#seeAlso> ?colid . }
   OPTIONAL { ?aug treat:augmentsTaxonConcept ?tc . }
   OPTIONAL { ?def treat:definesTaxonConcept ?tc . }
   OPTIONAL { ?dpr treat:deprecates ?tc . }
@@ -616,41 +663,46 @@ GROUP BY ?tn ?name ?tc`;
           ).then((
             json: SparqlJson,
           ) =>
-            json.results.bindings.filter((t) => t.tc).map((t) => {
-              return {
-                taxonConceptUri: t.tc.value,
-                taxonName: makeTaxonName(
-                  t.tn.value,
-                  t.name?.value,
-                  t.trtns?.value.split("|"),
-                  t.citetns?.value.split("|"),
-                ),
-                taxonConceptAuthority: t.authority?.value,
-                justifications: new JustificationSet(
-                  t.justs?.value.split("|").map((url) => {
-                    if (!this.treatments.has(url)) {
-                      this.treatments.set(url, {
-                        url,
-                        details: getTreatmentDetails(url),
-                      });
-                    }
-                    return {
-                      toString: () =>
-                        `${t.tc.value} deprecates ${taxon.taxonConceptUri} according to ${url}`,
-                      precedingSynonym: taxon,
-                      treatment: this.treatments.get(url),
-                    };
-                  }),
-                ),
-                treatments: {
-                  def: makeTreatmentSet(t.defs?.value.split("|")),
-                  aug: makeTreatmentSet(t.augs?.value.split("|")),
-                  dpr: makeTreatmentSet(t.dprs?.value.split("|")),
-                  cite: makeTreatmentSet(t.cites?.value.split("|")),
-                } as Treatments,
-                loading: true,
-              };
-            }), (error) => {
+            json.results.bindings.filter((t) => t.tc).map(
+              (t): JustifiedSynonym => {
+                return {
+                  taxonConceptUri: t.tc.value,
+                  taxonName: makeTaxonName(
+                    t.tn.value,
+                    t.name?.value,
+                    t.trtns?.value.split("|"),
+                    t.citetns?.value.split("|"),
+                  ),
+                  taxonConceptAuthority: t.authority?.value,
+                  colID: t.colids?.value.split("|").filter((s) =>
+                    s.startsWith("https://www.catalogueoflife.org/data/taxon/")
+                  ),
+                  justifications: new JustificationSet(
+                    t.justs?.value.split("|").map((url) => {
+                      if (!this.treatments.has(url)) {
+                        this.treatments.set(url, {
+                          url,
+                          details: getTreatmentDetails(url),
+                        });
+                      }
+                      return {
+                        toString: () =>
+                          `${t.tc.value} deprecates ${taxon.taxonConceptUri} according to ${url}`,
+                        precedingSynonym: taxon,
+                        treatment: this.treatments.get(url),
+                      };
+                    }),
+                  ),
+                  treatments: {
+                    def: makeTreatmentSet(t.defs?.value.split("|")),
+                    aug: makeTreatmentSet(t.augs?.value.split("|")),
+                    dpr: makeTreatmentSet(t.dprs?.value.split("|")),
+                    cite: makeTreatmentSet(t.cites?.value.split("|")),
+                  } as Treatments,
+                  loading: true,
+                };
+              },
+            ), (error) => {
             console.warn("SPARQL Error: " + error);
             return [];
           });
diff --git a/main.ts b/main.ts
index c41e4df..5747b29 100644
--- a/main.ts
+++ b/main.ts
@@ -20,7 +20,15 @@ try {
   for await (const synonym of synoGroup) {
     console.log(
       Colors.red(
-        ` * Found synonym: ${tcName(synonym)} <${synonym.taxonConceptUri}>`,
+        ` * Found synonym: ${tcName(synonym)} <${synonym.taxonConceptUri}>${
+          synonym.colID.length
+            ? ` [CoL: ${
+              synonym.colID.map((id) =>
+                id.replace("https://www.catalogueoflife.org/data/taxon/", "")
+              ).join(", ")
+            }]`
+            : ""
+        }`,
       ),
     );
     console.log(
@@ -30,9 +38,9 @@ try {
         } <${synonym.taxonName.uri}>`,
       ),
     );
-    synonym.taxonName.vernacularNames.then((v) =>
-      console.log(JSON.stringify(v))
-    );
+    synonym.taxonName.vernacularNames.then((v) => {
+      if (Object.getOwnPropertyNames(v).length) console.log(JSON.stringify(v));
+    });
     for (const treatment of synonym.taxonName.treatments.aug) {
       console.log(
         Colors.gray(
diff --git a/npm-package/package-lock.json b/npm-package/package-lock.json
index c7968cf..e4a30d1 100644
--- a/npm-package/package-lock.json
+++ b/npm-package/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@factsmission/synogroup",
-  "version": "2.2.0",
+  "version": "2.3.0-0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@factsmission/synogroup",
-      "version": "2.2.0",
+      "version": "2.3.0-0",
       "license": "MIT",
       "devDependencies": {
         "typescript": "^4.9.5"
diff --git a/npm-package/package.json b/npm-package/package.json
index 4cc298a..55ac34c 100644
--- a/npm-package/package.json
+++ b/npm-package/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@factsmission/synogroup",
-  "version": "2.2.0",
+  "version": "2.3.0-0",
   "description": "",
   "main": "index.js",
   "scripts": {