Scots Heraldry: A Practical Handbook on the Historical Principles and Modern ... - Sir Thomas Innes of Learney - Google Books

https://books.google.de/books?id=7JBG85_ayZIC&pg=PA39&lpg=PA39&dq=slughorn+slogan&source=bl&ots=XA45nN41az&sig=AcC81YGBE4UR6IRK6

This is the standard reference work on all aspects of Scottish heraldry with complete details on the history, science and practice. It contains abundant references to original sources of information and full details on the procedure for obtaining a grant.