On Connections with Totally Skew-Symmetric Torsion on Manifolds with Additional Tensor Structures and Indefinite Metrics, 2nd International Colloquium on Differential Geometry, September 6-10, 2010, Veliko Tarnovo University, Veliko Tarnovo, Bulgaria.

On the Geometry of Connections with Totally Skew-Symmetric Torsion on Manifolds with Additional Tensor Structures and Indefinite Metrics, Differential Geometry and its Applications, August 27-31, 2010, Masaryk University, Brno, Czech Republic.

Connections with parallel torsion on almost contact manifolds with B-metric, Selcuk University, Konya, Turkey, June 30, 2010.

Connections with parallel torsion on almost hypercomplex manifolds with pseudo-Hermitian structure, University of Nis, Nis, Serbia, April 30, 2010.

Quaternionic Kaehler Manifolds with Hermitian and Norden Metrics, 3rd MASSEE International Congress on Mathematics - MICOM 2009, Ohrid, Macedonia, September 16-20, 2009.

On the Geometry of the Connection with Totally Skew-Symmetric Tor-sion on a Class of Riemannian Almost Product Manifolds, 3rd MASSEE International Congress on Mathematics - MICOM 2009, Ohrid, Macedonia, September 16-20, 2009.

KT-connection on Riemannian Almost Product W3-manifolds, 9th International Conference on Geometry and Applications. Varna, September 5-10, 2009.

On Geometry of Manifolds with Hypercomplex Structure and Norden Metric, Johannes Kepler University of Linz, Linz, Austria, May 11, 2009.

Teaching of Geometrical Design for Computer Science Students, University of Alicante, Alicante, Spain, February 19, 2009.

Commonly Used Approaches to Learning, Teaching and Assessment in Mathematics, Universidad De La Sabana, Bogota, Colombia, October 9, 2008.

The Bezier Method in Geometric Design, Universidad Los Libertadores, Bogota, Colombia, October 8, 2008.

Tuning Educational Structures in Europe and Latin America, Universidad ECCI - Escuela Colombiana de Carreras Industriales, Bogota, Colombia, October 7, 2008.

Commonly Used Approaches to Learning, Teaching and Assessment, Universidad Los Libertadores, Bogota, Colombia, October 6, 2008.

Approaches to Learning, Teaching and Assessment, Universidad Los Libertadores, Bogota, Colombia, October 3, 2008.

Commonly Used Approaches to Learning, Teaching and Assessment in Mathematics, Universidad Los Libertadores, Bogota, Colombia, October 3, 2008.

Flows in the Networks, Universidad Los Libertadores, Bogota, Colombia, September 30, 2008.

Approaches to Teaching, Learning and Assessment in Competence Based Degree Programmes, Universidad Los Libertadores, Bogota, Colombia, September 29, 2008.

Tuning Project and its Relation to the Bologna Process, Universidad Los Libertadores, Bogota, Colombia, September 23, 2008.

General Presentation of the Tuning Methodology, Universidad Los Libertadores, Bogota, Colombia, September 16, 2008.

On the curvature properties of real time-like hypersurfaces of a Kaehler manifold with Norden metric. 9th International Workshop on Complex Structures, Integrability and Vector Fields, Sofia, August 25-29, 2008.

Curves in Computer-Aided Geometric Design. University of Helsinki, Helsinki, Finland, May 25, 2008.

Lie groups as quasi-Kähler manifolds with Killing Norden metric. 8th International Conference on Geometry and Applications. Varna, September 3-8, 2007.

On the geometry of quasi-Kähler manifolds with Norden metric. 4th International Conference on Applied Mathematics and Computing, Plovdiv, August 12-18, 2007.

On the geometry of quasi-Kähler manifolds with Norden metric. 8th International Work­shop on Complex Structures and Vector Fields, Sofia, August 21-26, 2006.

On the geometry of quasi-Kähler manifolds with Norden metric. A Lie group as a 4-dimensional example, 30th Conference on Differential Geometry, Będlewo, Poland, September, 2005.

Experience of Faculty of Mathematics and Informatics of Plovdiv University "Paisii Hilendarski" with International Projects, Seminar "Profession - Scientist" of the EU-Project “REKS - Researchers in European Knowledge Society”, “Researchers in Europe” Initiative FP6-019363, Plovdiv, September 20, 2005.

On the geometry of quasi-Kähler manifolds with Norden metric. A Lie group as a 4-dimensional example (authors: Gribachev-Manev-Mekerov), 7th International Conference on Geometry and Applications, Varna, September 4-10, 2005.

Four-dimensional almost hypercomplex pseudo-Hermitian manifolds, 7th International Work­shop on Complex Structures and Vector Fields, Plovdiv, August 31 – September 4, 2004.

Four-dimensional almost hypercomplex pseudo-Hermitian manifolds, 7th International Workshop on Complex Structures and Vector Fields, Plovdiv, September 2004.

Four-dimensional examples of almost hypercomplex pseudo-Hermitian manifolds, 31. Arbeitstagung über Geometrie und Algebra, Bedlewo, Poland, March 2004.

On examples of almost hypercomplex pseudo-Hermitian manifolds, International Symposium on Geometry - Kuju Meeting, Kuju, Oita, Japan, September 2003.

On curvature properties on some three-dimensional almost contact manifolds with B-metric, 5th International Conference on Geometry, Integrability and Quantization, Varna, June 5–12, 2003

On hypercomplex pseudo-Hermitian manifolds, 6th International Workshop on Complex Structures and Vector Fields, Varna, September 2002.

ISO9001 and higher education, Workshop on Computer technologies in quality management after the European Standards ISO9000, Lisbon, June 2002.

Examples of almost contact B-metric manifolds as real hypersurfaces, 5th International Conference on Geometry and Applications, Varna, August 24-29, 2001.

Real hypersurfaces of a Kaehlerian manifold with B-metric. Classification of the almost contact B-metric hypersurfaces, 28. Arbeitstagung über Geometrie und Algebra, München, 13-18.03. 2001.

On the curvature properties of almost contact B-metric hypersurfaces of Kaehlerian manifolds with B-metric, Jubilee Conference “30 Years FMI”, Plovdiv, November 1-3, 2000.

On almost paracontact Riemannian manifolds of type (n,n). 4th International Conference on Geometry and Applications, Varna, 1999.

Groups of contactly conformal transformations of almost contact manifolds with B-metric. 3rd International Conference on Geometry (dedicated to the 90th anniversary of Acad. Prof. Dr. Sci. Boyan Petkanchin), Varna, 1997.

Examples of almost contact B-metric manifolds of some special classes. 26th Spring Conference of UBM, Plovdiv, 1997.

On the conformal geometry of almost contact manifolds with B-metric. Scientific Session dedicated to the 100th anniversary of Acad. Prof. Dr. Sci. Nikola Obreshkov, Sofia, 1996.

Properties of curvature tensors on almost contact manifolds with B-metric. Jubilee Scientific Session of Vassil Levsky Higher Military School, Veliko Tarnovo, 1993.