Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE organisation_Types (organisation_type VARCHAR, organisation_type_description VARCHAR)
TABLE: CREATE TABLE Grants (grant_id VARCHAR, organisation_id VARCHAR, grant_amount VARCHAR)
TABLE: CREATE TABLE Organisations (organisation_id VARCHAR, organisation_type VARCHAR)
TABLE: CREATE TABLE documents (sent_date VARCHAR, grant_id VARCHAR)

### Question ###
Find out the send dates of the documents with the grant amount of more than 5000 were granted by organisation type described

### Accurate SQL ###

SELECT T1.sent_date FROM documents AS T1 JOIN Grants AS T2 ON T1.grant_id = T2.grant_id JOIN Organisations AS T3 ON T2.organisation_id = T3.organisation_id JOIN organisation_Types AS T4 ON T3.organisation_type = T4.organisation_type WHERE T2.grant_amount > 5000 AND T4.organisation_type_description = 'Research'