• 5-12 July, 2013, work period on Applied Mathematics, Al Neelain. University, Khartoum, Sudan.

• 15-20 December, 2012, the 20th Texas Symposuiom on Relativistic Astrophysics, Sao Paulo, Brazil.

• 1-15 December, 2011 The Cape Town international Cosmology school at University of Stallenbosch, Cape Town, South

Africa.

• 12-13 September, 2011 SOUTH AFRICAN GRAVITY SOCIETY (SAGS) conference, At Rhodes University, Graham stown, South Africa.

• 6-7 April, 2009 SOUTH AFRICAN GRAVITY SOCIETY (SAGS) conference, University of Kwazulu Natal, South Africa.